# CO vs SZOS

The clearest difference is rating: CO at 4.5 against SZOS's 2.8. CO also leads on review sentiment (27% vs 5%) and ratings volume (1.2K vs 105). On price, update cadence, ads 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.

CO holds the better App Store score, 4.5 against 2.8. That said, the two scores are not equally well evidenced: CO has 1.2K ratings behind it against 105, so its average is the more settled of the two. Written reviews point the same way: 27% of CO's written reviews are positive against 5% of SZOS's.

CO ships an update fortnightly, SZOS every 3 weeks. The most recent releases landed on October 19, 2026 and October 18, 2026 respectively.

## The numbers

| Metric | CO | SZOS |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.5 (1.2K ratings)](https://appshunter.io/ios/app/co-fit/id1514529526/reviews)** | [2.8 (105 ratings)](https://appshunter.io/ios/app/szos/id1543848875/reviews) |
| Number of ratings | **1.2K** | 105 |
| Positive reviews | **27.2% of reviews** | 5.3% of reviews |
| In-app purchases | No | No |
| Ads | Yes | Yes |
| Update frequency | **Fortnightly** | Every 3 weeks |
| Monetization | Ad-supported | Ad-supported |
| Size | 687 MB | 70 MB |
| Requires iOS | 14 | **13.0** |
| Devices | iPhone, iPod | iPhone, iPod |
| Age rating | 12+ | 4+ |
| Developer | [深圳叩鼎科技有限责任公司](https://appshunter.io/developer/1514529525) | [晟 谷](https://appshunter.io/developer/1543671031) |

## What reviewers say

### CO

[App page](https://appshunter.io/ios/app/co-fit/id1514529526)

This app syncs data from a smartwatch, including steps, heart rate, and sleep. It also pushes phone notifications to the watch and allows for watch configuration like alarms and weather updates. Health data is for reference only and not for medical use.

**Highlights:** Sync steps, calories, heart rate, sleep, and exercise, Display data intuitively with a new UI, Push phone calls and text messages to the watch, Configure watch alarms, schedules, and backlighting, Sync weather and AGPS files for watch location, Access iPhone Health for real-time data sync

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

**In-app purchases:** none

**What reviewers like**

- 👍 Easy to connect
- 🤩 Great watch and app experience
- 🤩 Awesome watch
- 👍 Good for the price
- 👍 Looks good

**What reviewers complain about**

- 🐛 Bluetooth connection issues
- 🐛 App crashes and freezes
- 🐛 Inaccurate measurements
- 🐛 Notifications not working
- 🐛 Firmware issues after updates

**Reported bugs**

- Time setting not working
- Watch disconnecting frequently
- Inaccurate step and distance tracking
- Inability to change weight in user profile
- Firmware update bricking the watch

**Requested features**

- More watch face designs
- Customization options for watch faces
- Integration with Apple Health
- Ability to remove unwanted features
- Better language support


### 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 CO free?

CO 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, CO or SZOS?

CO is rated higher. CO averages 4.5 out of 5 from 1.2K ratings, while SZOS averages 2.8 from 105 ratings.

### Do CO or SZOS have ads?

Both CO and SZOS show ads.

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

CO ships an update fortnightly, and SZOS every 3 weeks. Most recently, CO was updated on October 19, 2026 and SZOS on October 18, 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.*