# System Activity Monitors vs Unit Converter | Converter4U

The clearest difference is in-app purchases: Unit Converter | Converter4U at none against System Activity Monitors's 4. Unit Converter | Converter4U also leads on rating (4.6 vs 4.2) and iOS requirement (9.0 vs 13.0). System Activity Monitors's advantage is review sentiment (76% vs 57%) and ratings volume (778 vs 194). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. System Activity Monitors sells 4 in-app purchases, starting at $3.99 per 7 days. Unit Converter | Converter4U asks for nothing beyond the download.

Unit Converter | Converter4U holds the better App Store score, 4.6 against 4.2. Both are backed by a comparable volume of ratings — 778 and 194 respectively. Written reviews complicate that: 76% of System Activity Monitors's written reviews are positive against 57% of Unit Converter | Converter4U's, so the app with the better star average is not the one people write more warmly about.

System Activity Monitors ships an update every 3 months, Unit Converter | Converter4U every 4 months. Both last shipped on November 1, 2026.

## The numbers

| Metric | System Activity Monitors | Unit Converter | Converter4U |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.2 (778 ratings)](https://appshunter.io/ios/app/system-activity-monitors/id386118145/reviews) | **[4.6 (194 ratings)](https://appshunter.io/ios/app/unit-converter-converter4u/id620969788/reviews)** |
| Number of ratings | **778** | 194 |
| Positive reviews | **76.0% of reviews** | 57.1% of reviews |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 3 months** | Every 4 months |
| Monetization | Free with in-app purchases | **Free** |
| Size | 28 MB | 51 MB |
| Requires iOS | 13.0 | **9.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Tekton Technologies (P) Ltd.](https://appshunter.io/developer/343534621) | [VisTech.Projects LLC](https://appshunter.io/developer/620969851) |

## What reviewers say

### System Activity Monitors

[App page](https://appshunter.io/ios/app/system-activity-monitors/id386118145)

Monitor your device's health with this comprehensive tool. Track memory, battery performance, storage, and network details. Get detailed camera information and helpful battery-saving tips to optimize your iPhone.

**Highlights:** Memory usage tracking, Battery performance monitoring, Device IP and hardware address, Battery saving tips, Used and free space indicator, Detailed camera information, System and hardware specs

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Sysmon Pro | $3.99 | per 7 days |
| Sysmon Pro | $6.99 | per month |
| Sysmon Pro | $29.99 | per year |
| Real Time Graphs | $2.99 | one-time |

**What reviewers like**

- 💯 Excellent app
- 🎆 Great app
- 🔒 Respects privacy
- 🔋 Helpful battery tips
- 👍 Simple and straightforward

**What reviewers complain about**

- 🐛 Buggy updates
- 💰 Subscription-based model
- 🔒 Privacy concerns due to required login
- 🔍 Limited functionality for free version
- 🔍 Inaccurate device information

**Reported bugs**

- Crashes on certain devices
- Login/registration issues
- Incorrect memory/CPU usage reporting

**Requested features**

- Ability to close/manage running apps
- More detailed app-level usage breakdown
- Dark mode option
- Widgets for quick access
- Ability to reclaim memory/free up storage


### Unit Converter | Converter4U

[App page](https://appshunter.io/ios/app/unit-converter-converter4u/id620969788)

This app provides a powerful and intuitive way to convert between a wide range of units, including length, weight, temperature, and more. It offers simultaneous conversion of multiple units and customizable options for a personalized experience. Get instant, accurate results for all your conversion needs.

**Highlights:** Simultaneous multi-unit conversion, Customizable unit options, Copy converted values to clipboard, Supports numerous measurement categories, Intuitive and user-friendly interface

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none

**What reviewers like**

- 👍 Best free app
- 👍 Simple and precise
- 👍 Super!
- 👍 The best program!
- 👍 Great App

**What reviewers complain about**

- 🐛 Missing PSI conversion
- 🐛 Lacks quarts and gallons for volume
- 🐛 Precision issues with imperial units
- 🐛 Cumbersome UI
- 🐛 Limited conversion types

**Reported bugs**

- Input values not appearing
- White text on white background
- No numbers shown on iPhone 12 mini
- Precision issues with imperial units

**Requested features**

- Landscape display
- More conversion types/categories
- Support for PSI
- Support for quarts and gallons
- Improved precision for imperial units


## Frequently asked questions

### Is System Activity Monitors free?

System Activity Monitors is free to download, with in-app purchases available.

### Is Unit Converter | Converter4U free?

Unit Converter | Converter4U is free to download, with no in-app purchases.

### Which has better reviews, System Activity Monitors or Unit Converter | Converter4U?

Unit Converter | Converter4U is rated higher. System Activity Monitors averages 4.2 out of 5 from 778 ratings, while Unit Converter | Converter4U averages 4.6 from 194 ratings.

### Do System Activity Monitors or Unit Converter | Converter4U have ads?

Neither System Activity Monitors nor Unit Converter | Converter4U shows ads.

### Which is updated more often, System Activity Monitors or Unit Converter | Converter4U?

System Activity Monitors ships an update every 3 months, and Unit Converter | Converter4U every 4 months. Most recently, System Activity Monitors was updated on November 1, 2026 and Unit Converter | Converter4U on November 1, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*