# III vs B737 MRG

The clearest difference is price: B737 MRG at Free against III's $2.99. B737 MRG also leads on rating (4.9 vs 4.0) and update cadence (monthly vs every 17 months). III's advantage is in-app purchases (none vs 1) and review sentiment (100% vs 81%). On ads and device support there is nothing between them.

B737 MRG is free to download; III costs $2.99 up front. B737 MRG sells 1 in-app purchase, starting at $9.99 per year. III asks for nothing beyond the download.

B737 MRG holds the better App Store score, 4.9 against 4.0. That said, the two scores are not equally well evidenced: B737 MRG has 292 ratings behind it against 1, so its average is the more settled of the two. Written reviews complicate that: 100% of III's written reviews are positive against 81% of B737 MRG's, so the app with the better star average is not the one people write more warmly about.

III ships an update every 17 months, B737 MRG monthly. The most recent releases landed on October 2, 2026 and October 13, 2026 respectively.

## The numbers

| Metric | III | B737 MRG |
| --- | --- | --- |
| Price | $2.99 | **Free** |
| Rating | [4.0 (1 ratings)](https://appshunter.io/ios/app/iii-v-comp/id475184953/reviews) | **[4.9 (292 ratings)](https://appshunter.io/ios/app/b737-mrg/id481163421/reviews)** |
| Number of ratings | 1 | **292** |
| Positive reviews | **100.0% of reviews** | 81.3% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 17 months | **Monthly** |
| Monetization | **Paid** | Subscription |
| Size | 10 MB | 94 MB |
| Requires iOS | **11.0** | 16.6 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Takuya Ishikawa](https://appshunter.io/developer/468311118) | [MCC (BV)](https://appshunter.io/developer/421126411) |

## What reviewers say

### III

[App page](https://appshunter.io/ios/app/iii-v-comp/id475184953)

Calculate material properties for III-V compound semiconductors like AlGaInAsP. It determines compositions, lattice constant, strain, bandgap, and effective masses for InP or GaAs substrates.

**Highlights:** III-V compound semiconductor calculations, Material property determination, Composition calculation (x, y, z), Lattice constant and strain analysis, Bandgap and effective mass calculation, Supports InP and GaAs substrates

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

**In-app purchases:** none


### B737 MRG

[App page](https://appshunter.io/ios/app/b737-mrg/id481163421)

This professional reference app provides airline pilots with detailed guidance and practical advice for handling over 300 non-normal situations on the Boeing 737. It includes extensive system notes, illustrations, logic gates, and schematics to aid in-flight and ground operations.

**Highlights:** 300+ non-normal procedures, System notes and practical advice, Over 2,200 illustrations, Logic gates and schematics, Covers CL, NG, MAX editions, Regular content updates

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Yearly Subscription | $9.99 | per year |

**What reviewers like**

- 🚀 Excellent resource for 737 pilots
- 👍 Detailed and comprehensive information
- 🔍 Helpful for training and sim prep
- 💡 Provides deeper understanding of systems and procedures
- 🤓 Valuable addition to company manuals

**What reviewers complain about**

- 🐛 Occasional app crashes and bugs
- 💰 Transition to subscription model frustrates some users
- 📱 Compatibility issues with some iOS updates

**Reported bugs**

- App crashing on startup after updates
- Losing downloaded data on app restart
- Difficulty exiting demo mode

**Requested features**

- Interactive features like switchable diagrams
- Availability on macOS/desktop platforms


## Frequently asked questions

### Is III free?

III costs $2.99, with no in-app purchases.

### Is B737 MRG free?

B737 MRG is free to download, with in-app purchases available.

### Which has better reviews, III or B737 MRG?

B737 MRG is rated higher. III averages 4.0 out of 5 from 1 ratings, while B737 MRG averages 4.9 from 292 ratings.

### Do III or B737 MRG have ads?

Neither III nor B737 MRG shows ads.

### Which is updated more often, III or B737 MRG?

III ships an update every 17 months, and B737 MRG monthly. Most recently, III was updated on October 2, 2026 and B737 MRG on October 13, 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.*