# pdf vs 아이두

The clearest difference is price: 아이두 at Free against pdf's $9.99. 아이두 also leads on rating (5.0 vs 4.4) and update cadence (every 2 days vs every 2 weeks). pdf's advantage is in-app purchases (none vs 2) and ratings volume (27 vs 1). On ads, device support and iOS requirement there is nothing between them.

아이두 is free to download; pdf costs $9.99 up front. 아이두 sells 2 in-app purchases, starting at $2.99 per month. pdf asks for nothing beyond the download.

아이두 holds the better App Store score, 5.0 against 4.4. That said, the two scores are not equally well evidenced: pdf has 27 ratings behind it against 1, so its average is the more settled of the two.

pdf ships an update every 2 weeks, 아이두 every 2 days. The most recent releases landed on October 9, 2026 and October 1, 2026 respectively.

## The numbers

| Metric | pdf | 아이두 |
| --- | --- | --- |
| Price | $9.99 | **Free** |
| Rating | [4.4 (27 ratings)](https://appshunter.io/ios/app/pdf-notes-for-ipad/id417200844/reviews) | **[5.0 (1 ratings)](https://appshunter.io/ios/app/ai/id6757722325/reviews)** |
| Number of ratings | **27** | 1 |
| Positive reviews | 71.5% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 2 weeks | **Every 2 days** |
| Monetization | Paid | **Freemium** |
| Size | 138 MB | 107 MB |
| Requires iOS | **16.0** | 16.4 |
| Devices | iPad | **iPhone, iPad** |
| Age rating | 4+ | 4+ |
| Developer | [AMuseTec Co., Ltd.](https://appshunter.io/developer/342152781) | [yongmin kim](https://appshunter.io/developer/1868466447) |

## What reviewers say

### pdf

[App page](https://appshunter.io/ios/app/pdf-notes-for-ipad/id417200844)

Manage and annotate PDF files on your iPad with fast page turning and intuitive finger-writing. Easily import, organize, and share your notes with friends. Offers a seamless reading and editing experience.

**Highlights:** Fast page turning and content scanning, Intuitive finger-writing with zoom-in, Easy PDF import via Dropbox, Email, or iTunes, Organized bookshelves with search, Variety of pens, highlighters, and text notes, Export annotated PDFs via email

**Features:** Vision Pro support

**In-app purchases:** none


### 아이두

[App page](https://appshunter.io/ios/app/ai/id6757722325)

This app uses AI to help you manage your daily tasks and stay motivated with friends. It organizes your to-dos automatically, tracks your progress, and allows you to share your goals and achievements with others for mutual encouragement.

**Highlights:** AI-powered task parsing and organization, Social sharing of to-dos with friends, Progress tracking and achievement streaks, Customizable reminders and notifications, Color-coded task categorization, Weekly and monthly AI reports (Pro)

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Aido Pro | $2.99 | per month |
| Aido Pro | $19.99 | per year |


## Frequently asked questions

### Is pdf free?

pdf costs $9.99, with no in-app purchases.

### Is 아이두 free?

아이두 is free to download, with in-app purchases available.

### Which has better reviews, pdf or 아이두?

아이두 is rated higher. pdf averages 4.4 out of 5 from 27 ratings, while 아이두 averages 5.0 from 1 ratings.

### Do pdf or 아이두 have ads?

Neither pdf nor 아이두 shows ads.

### Which is updated more often, pdf or 아이두?

pdf ships an update every 2 weeks, and 아이두 every 2 days. Most recently, pdf was updated on October 9, 2026 and 아이두 on October 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.*