diff --git a/.changeset/khaki-apples-retire.md b/.changeset/khaki-apples-retire.md
new file mode 100644
index 00000000000..d116392de85
--- /dev/null
+++ b/.changeset/khaki-apples-retire.md
@@ -0,0 +1,6 @@
+---
+"effect": minor
+"@effect/vitest": minor
+---
+
+Improve custom matchers
diff --git a/packages/effect/src/Equal.ts b/packages/effect/src/Equal.ts
index 440e36c9fa7..f6d7ac66b1d 100644
--- a/packages/effect/src/Equal.ts
+++ b/packages/effect/src/Equal.ts
@@ -4,7 +4,6 @@
 import type { Equivalence } from "./Equivalence.js"
 import * as Hash from "./Hash.js"
 import { hasProperty } from "./Predicate.js"
-import { structuralRegionState } from "./Utils.js"
 
 /**
  * @since 2.0.0
@@ -44,41 +43,14 @@ function compareBoth(self: unknown, that: unknown): boolean {
   if (selfType === "object" || selfType === "function") {
     if (self !== null && that !== null) {
       if (isEqual(self) && isEqual(that)) {
-        if (Hash.hash(self) === Hash.hash(that) && self[symbol](that)) {
-          return true
-        } else {
-          return structuralRegionState.enabled && structuralRegionState.tester
-            ? structuralRegionState.tester(self, that)
-            : false
-        }
+        return Hash.hash(self) === Hash.hash(that) && self[symbol](that)
       } else if (self instanceof Date && that instanceof Date) {
         return self.toISOString() === that.toISOString()
       }
     }
-    if (structuralRegionState.enabled) {
-      if (Array.isArray(self) && Array.isArray(that)) {
-        return self.length === that.length && self.every((v, i) => compareBoth(v, that[i]))
-      }
-      if (Object.getPrototypeOf(self) === Object.prototype && Object.getPrototypeOf(self) === Object.prototype) {
-        const keysSelf = Object.keys(self as any)
-        const keysThat = Object.keys(that as any)
-        if (keysSelf.length === keysThat.length) {
-          for (const key of keysSelf) {
-            // @ts-expect-error
-            if (!(key in that && compareBoth(self[key], that[key]))) {
-              return structuralRegionState.tester ? structuralRegionState.tester(self, that) : false
-            }
-          }
-          return true
-        }
-      }
-      return structuralRegionState.tester ? structuralRegionState.tester(self, that) : false
-    }
   }
 
-  return structuralRegionState.enabled && structuralRegionState.tester
-    ? structuralRegionState.tester(self, that)
-    : false
+  return false
 }
 
 /**
diff --git a/packages/effect/src/Hash.ts b/packages/effect/src/Hash.ts
index ec81836bafa..531f2ac70ec 100644
--- a/packages/effect/src/Hash.ts
+++ b/packages/effect/src/Hash.ts
@@ -4,7 +4,6 @@
 import { pipe } from "./Function.js"
 import { globalValue } from "./GlobalValue.js"
 import { hasProperty } from "./Predicate.js"
-import { structuralRegionState } from "./Utils.js"
 
 /** @internal */
 const randomHashCache = globalValue(
@@ -31,10 +30,6 @@ export interface Hash {
  * @category hashing
  */
 export const hash: <A>(self: A) => number = <A>(self: A) => {
-  if (structuralRegionState.enabled === true) {
-    return 0
-  }
-
   switch (typeof self) {
     case "number":
       return number(self)
diff --git a/packages/effect/src/Utils.ts b/packages/effect/src/Utils.ts
index 618d0a6d7d6..003970d42fd 100644
--- a/packages/effect/src/Utils.ts
+++ b/packages/effect/src/Utils.ts
@@ -2,7 +2,6 @@
  * @since 2.0.0
  */
 import { identity } from "./Function.js"
-import { globalValue } from "./GlobalValue.js"
 import type { Kind, TypeLambda } from "./HKT.js"
 import { getBugErrorMessage } from "./internal/errors.js"
 import { isNullable, isObject } from "./Predicate.js"
@@ -751,43 +750,6 @@ export function yieldWrapGet<T>(self: YieldWrap<T>): T {
   throw new Error(getBugErrorMessage("yieldWrapGet"))
 }
 
-/**
- * Note: this is an experimental feature made available to allow custom matchers in tests, not to be directly used yet in user code
- *
- * @since 3.1.1
- * @status experimental
- * @category modifiers
- */
-export const structuralRegionState = globalValue(
-  "effect/Utils/isStructuralRegion",
-  (): { enabled: boolean; tester: ((a: unknown, b: unknown) => boolean) | undefined } => ({
-    enabled: false,
-    tester: undefined
-  })
-)
-
-/**
- * Note: this is an experimental feature made available to allow custom matchers in tests, not to be directly used yet in user code
- *
- * @since 3.1.1
- * @status experimental
- * @category modifiers
- */
-export const structuralRegion = <A>(body: () => A, tester?: (a: unknown, b: unknown) => boolean): A => {
-  const current = structuralRegionState.enabled
-  const currentTester = structuralRegionState.tester
-  structuralRegionState.enabled = true
-  if (tester) {
-    structuralRegionState.tester = tester
-  }
-  try {
-    return body()
-  } finally {
-    structuralRegionState.enabled = current
-    structuralRegionState.tester = currentTester
-  }
-}
-
 const tracingFunction = (name: string) => {
   const wrap = {
     [name]<A>(body: () => A) {
diff --git a/packages/effect/test/Hash.test.ts b/packages/effect/test/Hash.test.ts
index 3da943e6215..1ab9a62799c 100644
--- a/packages/effect/test/Hash.test.ts
+++ b/packages/effect/test/Hash.test.ts
@@ -1,36 +1,9 @@
-import * as Equal from "effect/Equal"
 import { absurd, identity } from "effect/Function"
 import * as Hash from "effect/Hash"
 import * as HashSet from "effect/HashSet"
-import * as Option from "effect/Option"
-import * as Utils from "effect/Utils"
 import { describe, expect, it } from "vitest"
 
 describe("Hash", () => {
-  it("structural", () => {
-    const a = { foo: { bar: "ok", baz: { arr: [0, 1, 2] } } }
-    const b = { foo: { bar: "ok", baz: { arr: [0, 1, 2] } } }
-    expect(Hash.hash(a)).not.toBe(Hash.hash(b))
-    expect(Equal.equals(a, b)).toBe(false)
-    Utils.structuralRegion(() => {
-      expect(Hash.hash(a)).toBe(Hash.hash(b))
-      expect(Equal.equals(a, b)).toBe(true)
-    })
-    expect(Hash.hash(a)).not.toBe(Hash.hash(b))
-    expect(Equal.equals(a, b)).toBe(false)
-  })
-  it("structural cached", () => {
-    const a = Option.some({ foo: { bar: "ok", baz: { arr: [0, 1, 2] } } })
-    const b = Option.some({ foo: { bar: "ok", baz: { arr: [0, 1, 2] } } })
-    expect(Hash.hash(a)).not.toBe(Hash.hash(b))
-    expect(Equal.equals(a, b)).toBe(false)
-    Utils.structuralRegion(() => {
-      expect(Hash.hash(a)).toBe(Hash.hash(b))
-      expect(Equal.equals(a, b)).toBe(true)
-    })
-    expect(Hash.hash(a)).not.toBe(Hash.hash(b))
-    expect(Equal.equals(a, b)).toBe(false)
-  })
   it("exports", () => {
     expect(Hash.string).exist
     expect(Hash.structureKeys).exist
diff --git a/packages/vitest/src/internal.ts b/packages/vitest/src/internal.ts
index 1b8cb9658a8..d4e138e0b00 100644
--- a/packages/vitest/src/internal.ts
+++ b/packages/vitest/src/internal.ts
@@ -3,18 +3,20 @@
  */
 import type { Tester, TesterContext } from "@vitest/expect"
 import * as Cause from "effect/Cause"
+import * as Chunk from "effect/Chunk"
 import * as Duration from "effect/Duration"
 import * as Effect from "effect/Effect"
-import * as Equal from "effect/Equal"
+import * as Either from "effect/Either"
 import * as Exit from "effect/Exit"
 import { flow, identity, pipe } from "effect/Function"
+import * as HashSet from "effect/HashSet"
 import * as Layer from "effect/Layer"
 import * as Logger from "effect/Logger"
+import * as Option from "effect/Option"
 import * as Schedule from "effect/Schedule"
 import type * as Scope from "effect/Scope"
 import * as TestEnvironment from "effect/TestContext"
 import type * as TestServices from "effect/TestServices"
-import * as Utils from "effect/Utils"
 import * as V from "vitest"
 import type * as Vitest from "./index.js"
 
@@ -41,14 +43,26 @@ const TestEnv = TestEnvironment.TestContext.pipe(
 )
 
 /** @internal */
-function customTester(this: TesterContext, a: unknown, b: unknown, customTesters: Array<Tester>) {
-  if (!Equal.isEqual(a) || !Equal.isEqual(b)) {
-    return undefined
+function customTester(this: TesterContext, _a: unknown, _b: unknown, _customTesters: Array<Tester>) {
+  if (Chunk.isChunk(_a) && Chunk.isChunk(_b)) {
+    return this.equals(Array.from(_a), Array.from(_b), _customTesters)
   }
-  return Utils.structuralRegion(
-    () => Equal.equals(a, b),
-    (x, y) => this.equals(x, y, customTesters.filter((t) => t !== customTester))
-  )
+  if (Option.isOption(_a) && Option.isOption(_b)) {
+    return _a._tag === _b._tag && (_a._tag === "None" || this.equals(_a.value, (_b as any).value, _customTesters))
+  }
+  if (Either.isEither(_a) && Either.isEither(_b)) {
+    return (Either.isLeft(_a) && Either.isLeft(_b) && this.equals(_a.left, _b.left, _customTesters)) ||
+      (Either.isRight(_a) && Either.isRight(_b) && this.equals(_a.right, _b.right, _customTesters))
+  }
+  if (Cause.isCause(_a) && Cause.isCause(_b)) {
+    return this.equals(Cause.failures(_a), Cause.failures(_b), _customTesters) &&
+      this.equals(Cause.defects(_a), Cause.defects(_b), _customTesters) &&
+      this.equals(Cause.interruptors(_a), Cause.interruptors(_b), _customTesters)
+  }
+  if (HashSet.isHashSet(_a) && HashSet.isHashSet(_b)) {
+    return this.equals(new Set(_a), new Set(_b), _customTesters)
+  }
+  return undefined
 }
 
 /** @internal */