DUO vs i
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
DUO
This multi-functional storage device offers a dual connector for seamless file transfer and management between Apple devices and computers. It allows for backing up contacts, streaming high-definition videos, and managing files directly from the device.
- Dual USB and Lightning connectors
- Contact backup and restore
- Independent music and video playback
- 1080p video streaming
- File management (copy, delete, export)
- Browse external and local files
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DUO-LINK 3 is a multi-functional storage device for Mac, PC, iPad, iPhone, and iPod touch. DUO-LINK 3 has a standard USB interface and a lightning connector for iPhone and iPad. Free up space on your iPhone and iPad. Transfer and share files between your iPhone, iPad & Mac or PC quickly and easily. DUO-LINK 3 Functions： ● Contact list backup and restore. ● Supports independent music and video playback. ● Stream 1080p videos directly from DUO-LINK 3. ● File management operations such as copy, delete, export etc. ● Browse files store on DUO-LINK 3 Drive. ● Browse local files stored within DUO-LINK 3 App. ● Transfer media and files from iPhone to DUO-LINK 3 Drive. Compatibility： ● IOS 9 and older versions. Compatible with : iPhone 6 Plus, iPad 4th Generation and older devices. ● PCs running Windows XP, Windows 7, and Windows 8. ● Mac computers running Mac OS 10.5 or later.
i
Easily manage all your files on iOS devices. Transfer documents, photos, music, and videos between different devices and platforms. Offers backup for contacts and camera roll, and supports a wide range of file formats.
- File management for iOS
- Cross-platform file exchange
- Backup contacts and camera roll
- Play videos and music
- Preview images
- Supports wide file formats
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The i-FlashDevice is the best way to manage all your files on iOS devices,Exchanges files with different devices & platforms with ease. 1.Backup Contacts and Camera Roll. 2.Play Videos,Musics. 3.Preview Images,World. Supported File Formats: Document:DOC,XLS,PPT,TXT,else; Image:JPG,JPEG,BMP,GIF,else; Audio:MP3,AAC,AIF,else; Video:MP4,MOV,MKV,AVI,FLV,RMVB,ELSE;
Screenshots
Verdict
The clearest difference is rating: DUO at 2.5 against i's 2.3. i's advantage is ratings volume (789 vs 86). On price, review sentiment, update cadence and ads there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
DUO holds the better App Store score, 2.5 against 2.3. That said, the two scores are not equally well evidenced: i has 789 ratings behind it against 86, so its average is the more settled of the two. Written reviews point the same way: 18% of DUO's written reviews are positive against 15% of i's.
Both ship on a similar rhythm, roughly every 3 months. Both last shipped on October 17, 2026.
| Parameter | DUO | i |
|---|---|---|
| Price | Free | Free |
| Rating | 2.5 (86 ratings) — better | 2.3 (789 ratings) |
| Positive reviews | 17.5% of reviews — better | 15.0% of reviews |
| Number of ratings | 86 | 789 — better |
| Update frequency | Every 3 months | Every 3 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 8.0 | 8.0 |
| Further details — not scored | ||
| Size | 34 MB | 89 MB |
| Age rating | 4+ | 4+ |
| Developer | Gopod Group Limited | ShenZhen 0101 technology Co.,Ltd |
Customer experience
DUO
i
User reviews
DUO
From 86 App Store ratingsWhat we love
- ✅ Easy file transfer between devices
- 📱 Works with multiple iOS devices
- 🎵 Can store and play media files
- 💾 Provides additional storage capacity
- 🔄 Simple backup functionality for photos/videos
Room to improve
- 🐛 Frequent app crashes and freezes
- ❌ Incompatible with newer iPhone models
- 📉 Poor app stability after updates
- 🔌 Hardware not recognized by app
- 💥 Data loss issues reported
i
From 789 App Store ratingsWhat we love
- ⭐ Cool app
- 🚀 Able to transfer files directly
- 📸 Can take photos/videos within the app
- 🗄️ Useful for backing up files
Room to improve
- 🐛 Crashes frequently
- ⚠️ Doesn't work with newer devices/iOS versions
- 🤖 Poor software quality and buggy
- 🔌 Drains device battery quickly
- 📂 Issues with file management and deletion
Bugs and requests
DUO
Reported bugs
21 issues- App crashes when playing MP3 files
- App crashes when transferring large files
- App crashes when viewing videos
- App crashes when adjusting volume during video playback
- App crashes when copying photos
Show 16 moreShow fewer
- App crashes after 15-20 seconds of use
- Cannot recognize iPhone 8, iPhone X, iPhone 14, iPhone 16 Pro
- Hardware not detected despite proper connection
- Files show as transferred but remain on device
- Duplicate file errors during transfer
- File names corrupted with special characters
- Cannot delete files after transfer
- App closes when opening audio files
- Cannot access audio files after update
- App bloats to 1-2GB after initial use
- Incompatible with iOS 11 and later versions
- LED light not activating on connection
- Chinese language files appearing unexpectedly
- Cannot read flash drive after disconnect/reconnect
- File transfer progress not completing despite appearing to work
- Photos not visible in app despite being on device
Requested features
15 requests- Video thumbnail preview functionality
- File sharing with other applications
- Password/file locking capability
- Ability to select multiple files in view mode
- Wireless streaming to Apple TV
Show 10 moreShow fewer
- Root folder naming per device
- Ability to rename files on iPhone
- Create folders and organize files
- App storage on external drive
- Better PDF reader for stored files
- Fast forward/rewind for audio/video
- Playback resume from last location
- Bookmark functionality for media
- Live photo support
- Document transfer capability
i
Reported bugs
4 issues- App crashes on launch
- Unable to connect to device
- Corrupted files after transfer
- Inconsistent behavior when viewing media
Requested features
4 requests- Add support for more file types
- Improve video playback functionality
- Provide better instructions and troubleshooting
- Optimize app for latest iOS versions
In-app purchases
DUO
No in-app purchases
i
No in-app purchases
