diff --git a/CHANGELOG.md b/CHANGELOG.md
index 057e81fb..d3df249c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -31,10 +31,12 @@ project adheres to [Semantic Versioning](http://semver.org/).
 - ci: switch out deprecated benchmark-regression library for replacement
 - AggregatorRegistry renamed to ClusterRegistry, old name deprecated
 - chore: update faceoff to 1.1
+- perf: Avoid array conversion in getMetricsAsJSON by directly iterating over metric values (~1.3% faster)
+- perf: Optimize string escaping for better metrics serialization
 
 ### Added
 
-- Expanded benchmarking code
+- Expanded benchmarks and using new benchmarking library
 - new WorkerRegistry to provide equivalent support to AggregatorRegistry
 
 ## [15.1.3] - 2024-06-27
diff --git a/benchmarks/defaultMetrics.js b/benchmarks/defaultMetrics.js
new file mode 100644
index 00000000..6663859a
--- /dev/null
+++ b/benchmarks/defaultMetrics.js
@@ -0,0 +1,58 @@
+'use strict';
+
+const Path = require('path');
+const { createRequire } = require('node:module');
+const { getLabelCombinations } = require('./utils/labels');
+
+let count = 1;
+
+module.exports = function setupSuites(benchmark) {
+	benchmark.suite('osMemoryHeap', suite => {
+		suite.add(
+			'new',
+			(client, { labels, metric: osMemoryHeap, registry }) =>
+				osMemoryHeap(registry, {
+					prefix: `heap${count++}`,
+					help: 'HeapUsed',
+					labels,
+				}),
+			{
+				setup: (client, location) =>
+					loadMetrics(client, location, 'osMemoryHeap'),
+				teardown,
+			},
+		);
+
+		suite.add('collect', async (client, { registry }) => registry.metrics(), {
+			setup: (client, location) => {
+				const ctx = loadMetrics(client, location, 'osMemoryHeap');
+				const { metric: osMemoryHeap, labels, registry } = ctx;
+
+				osMemoryHeap(registry, {
+					prefix: `heap${count++}`,
+					help: 'HeapUsed',
+					labels,
+				});
+
+				return { registry };
+			},
+			teardown,
+		});
+	});
+};
+
+function loadMetrics(client, location, metricName) {
+	const require = createRequire(location);
+	const fromModule = Path.join(location, `./lib/metrics/${metricName}`);
+	const combinations = getLabelCombinations([1], ['region', 'env']);
+
+	return {
+		metric: require(fromModule),
+		labels: combinations[0],
+		registry: new client.Registry(),
+	};
+}
+
+function teardown(client, { registry }) {
+	registry.clear();
+}
diff --git a/benchmarks/index.js b/benchmarks/index.js
index f6d4324e..341eff22 100644
--- a/benchmarks/index.js
+++ b/benchmarks/index.js
@@ -24,6 +24,7 @@ benchmarks.suite('histogram', require('./histogram'));
 benchmarks.suite('util', require('./util'));
 benchmarks.suite('summary', require('./summary'));
 benchmarks.suite('registry', require('./registry'));
+benchmarks.suite('default metrics', require('./defaultMetrics'));
 benchmarks.suite('cluster', require('./cluster'));
 
 benchmarks
diff --git a/benchmarks/util.js b/benchmarks/util.js
index 2d0c41cb..b21c8152 100644
--- a/benchmarks/util.js
+++ b/benchmarks/util.js
@@ -5,7 +5,7 @@ const Path = require('path');
 module.exports = setupUtilSuite;
 
 function setupUtilSuite(suite) {
-	const skip = ['prom-client@latest', 'prom-client@trunk'];
+	const skip = ['prom-client@latest'];
 
 	suite.add(
 		'hashObject',
diff --git a/index.js b/index.js
index dfef5adc..dc752cd2 100644
--- a/index.js
+++ b/index.js
@@ -38,4 +38,3 @@ exports.ClusterRegistry = require('./lib/cluster');
 exports.WorkerRegistry = require('./lib/worker');
 /** @deprecated */
 exports.AggregatorRegistry = exports.ClusterRegistry;
-exports[Symbol('util')] = require('./lib/util');
diff --git a/lib/registry.js b/lib/registry.js
index 4d0906b1..c9451717 100644
--- a/lib/registry.js
+++ b/lib/registry.js
@@ -137,7 +137,7 @@ class Registry {
 
 		const promises = [];
 
-		for (const metric of this.getMetricsAsArray()) {
+		for (const metric of this._metrics.values()) {
 			promises.push(metric.get());
 		}
 
@@ -293,11 +293,46 @@ function escapeLabelValue(str) {
 	if (typeof str !== 'string') {
 		return str;
 	}
-	return escapeString(str).replace(/"/g, '\\"');
+
+	let result = '';
+	for (let i = 0; i < str.length; i++) {
+		const char = str[i];
+		switch (char) {
+			case '\\':
+				result += '\\\\';
+				break;
+			case '\n':
+				result += '\\n';
+				break;
+			case '"':
+				result += '\\"';
+				break;
+			default:
+				result += char;
+		}
+	}
+
+	return result;
 }
+
 function escapeString(str) {
-	return str.replace(/\\/g, '\\\\').replace(/\n/g, '\\n');
+	let result = '';
+	for (let i = 0; i < str.length; i++) {
+		const char = str[i];
+		switch (char) {
+			case '\\':
+				result += '\\\\';
+				break;
+			case '\n':
+				result += '\\n';
+				break;
+			default:
+				result += char;
+		}
+	}
+	return result;
 }
+
 function standardizeCounterName(name) {
 	return name.replace(/_total$/, '');
 }