# RDFit vs SZOS

RDFit and SZOS both sit at 2.8 stars, but that hides the real split: 45% of RDFit's written reviews are positive against 5% of SZOS's. RDFit also leads on ads (none vs shown) and ratings volume (3.1K vs 105). On price, rating, update cadence and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

On the App Store both sit at effectively the same score — 2.8 for RDFit against 2.8 for SZOS. That said, the two scores are not equally well evidenced: RDFit has 3.1K ratings behind it against 105, so its average is the more settled of the two. Written reviews are what separate them: 45% of RDFit's written reviews are positive against 5% of SZOS's.

RDFit ships an update fortnightly, SZOS every 3 weeks. The most recent releases landed on October 14, 2026 and October 9, 2026 respectively.

## The numbers

| Metric | RDFit | SZOS |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[2.8 (3.1K ratings)](https://appshunter.io/ios/app/rdfit/id1493359248/reviews)** | [2.8 (105 ratings)](https://appshunter.io/ios/app/szos/id1543848875/reviews) |
| Number of ratings | **3.1K** | 105 |
| Positive reviews | **45.5% of reviews** | 5.3% of reviews |
| In-app purchases | No | No |
| Ads | **No** | Yes |
| Update frequency | **Fortnightly** | Every 3 weeks |
| Monetization | **Free** | Ad-supported |
| Size | 290 MB | 70 MB |
| Requires iOS | 13.0 | 13.0 |
| Devices | iPhone, iPod | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [深圳市润德智能通讯科技有限公司](https://appshunter.io/developer/1761719783) | [晟 谷](https://appshunter.io/developer/1543671031) |

## What reviewers say

### RDFit

[App page](https://appshunter.io/ios/app/rdfit/id1493359248)

This app synchronizes with HealthKit to read and write health data. It's developed by a company specializing in smart wearables and electronic products.

**Highlights:** HealthKit integration, Read Health data, Write Health data, Smart wearable device support, Electronic product integration

**In-app purchases:** none

**What reviewers like**

- 👍 Easy to use interface
- ⌚ Beautiful watch design and appearance
- ❤️ Health monitoring features (blood sugar, blood pressure)
- 🎨 Customizable watch faces available
- 📱 Good app connectivity when working properly

**What reviewers complain about**

- 🐛 Frequent app crashes and freezing
- 📲 Poor notification system (missing SMS/text messages)
- 🔌 Limited watch face customization (only one downloadable at a time)
- 🔗 Unreliable Bluetooth connection and pairing issues
- 📊 Inaccurate health metrics and sensor readings

**Reported bugs**

- App crashes on startup and during synchronization
- App crashes after recent updates
- Watch locks for no reason and cannot unlock
- GPS feature not connecting despite proper setup
- Automatic Bluetooth connection fails

**Requested features**

- Add more watch face options and styles
- Allow multiple watch faces to be downloaded simultaneously
- Implement SMS/text message notifications
- Add Apple Watch-style watch faces
- Enable custom watch face editing with more customization options


### SZOS

[App page](https://appshunter.io/ios/app/szos/id1543848875)

This app syncs with a smart watch to track your daily activity, including steps, heart rate, and sleep patterns. It provides insights into your health and fitness metrics.

**Highlights:** Step tracking, Heart rate monitoring, Sleep analysis, Syncs with smart watch, Activity mode

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

**In-app purchases:** none


## Frequently asked questions

### Is RDFit free?

RDFit is free to download, with no in-app purchases.

### Is SZOS free?

SZOS is free to download, with no in-app purchases.

### Which has better reviews, RDFit or SZOS?

RDFit is rated higher. RDFit averages 2.8 out of 5 from 3.1K ratings, while SZOS averages 2.8 from 105 ratings.

### Do RDFit or SZOS have ads?

SZOS shows ads; RDFit does not.

### Which is updated more often, RDFit or SZOS?

RDFit ships an update fortnightly, and SZOS every 3 weeks. Most recently, RDFit was updated on October 14, 2026 and SZOS on October 9, 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.*