# Catalytic Converter Guide vs BookWatch

The clearest difference is rating: BookWatch at 4.7 against Catalytic Converter Guide's 3.6. BookWatch also leads on ratings volume (14K vs 14) and chart position (#73 vs unranked). Catalytic Converter Guide's advantage is ads (none vs shown) and review sentiment (60% vs 51%). On price, update cadence, in-app purchases and monetization model there is nothing between them.

Both are free to download. Catalytic Converter Guide sells 2 in-app purchases, starting at $19.99 per month and BookWatch sells 22 in-app purchases, starting at $8.99 per month. Whichever you choose, the download price is not the number that matters.

BookWatch holds the better App Store score, 4.7 against 3.6. That said, the two scores are not equally well evidenced: BookWatch has 14K ratings behind it against 14, so its average is the more settled of the two. Written reviews complicate that: 60% of Catalytic Converter Guide's written reviews are positive against 51% of BookWatch's, so the app with the better star average is not the one people write more warmly about.

Both ship on a similar rhythm, roughly every 3 days. The most recent releases landed on October 24, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | Catalytic Converter Guide | BookWatch |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [3.6 (14 ratings)](https://appshunter.io/ios/app/catalytic-converter-guide/id1581315898/reviews) | **[4.7 (14K ratings)](https://appshunter.io/ios/app/bookwatch-visual-learning/id1660054787/reviews)** |
| Number of ratings | 14 | **14K** |
| Positive reviews | **60.0% of reviews** | 50.7% of reviews |
| In-app purchases | Yes | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 3 days | Every 3 days |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Best chart rank | — | **#73** |
| Size | 60 MB | 82 MB |
| Requires iOS | **12.1** | 17.0 |
| Devices | iPhone, iPod | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Colin Richardson](https://appshunter.io/developer/1751712265) | [Morfosis](https://appshunter.io/developer/1660054789) |

## What reviewers say

### Catalytic Converter Guide

[App page](https://appshunter.io/ios/app/catalytic-converter-guide/id1581315898)

Access a comprehensive database of over 10,000 catalytic converter codes, complete with current market prices and images. Search by serial number or browse by manufacturer to find detailed information and maximize your scrap value.

**Highlights:** Search by serial number, Browse by car manufacturer, View converter details (picture, make, price), Identify most expensive converters, Regularly updated data, Calculate scrap value

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly Subscription | $19.99 | per month |
| Yearly Subscription at $149.99 | $149.99 | per year |


### BookWatch

[App page](https://appshunter.io/ios/app/bookwatch-visual-learning/id1660054787)

**Currently charting:** #73 Top Free · Book, #87 Top Grossing · Book (US App Store)

This app transforms books into engaging video summaries, allowing you to watch fiction and non-fiction content like movies. Learn key insights from best-selling books through animated 30-minute videos, making learning fun and easy.

**Highlights:** Animated video book summaries, Learn from fiction and non-fiction, 30-minute video learning, Whiteboard animation style, Access best-selling books

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

**In-app purchases (22)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly Subscription | $8.99 | per month |
| Monthly Subscription | $12.99 | per month |
| BookWatch Premium | $14.99 | per month |
| BookWatch Premium 86% Offer | $19.99 | per year |
| Morfosis Premium | $24.99 | per month |
| BookWatch Premium Subscription | $29.99 | per year |
| Yearly Subscription | $39.99 | per year |
| BookWatch Premium Yearly | $39.99 | per year |
| BookWatch Premium Free Trial Annual | $49.99 | per year |
| BookWatch Premium Subscription | $49.99 | per year |
| BookWatch 7 day trial | $59.99 | per year |
| Yearly Premium Subscription | $59.99 | per year |
| BookWatch Premium Subscription | $59.99 | per year |
| Yearly Premium Subscription | $69.99 | per year |
| Bookwatch 7 day trial | $69.99 | per year |
| Annual Package - 7 Day Trial | $79.99 | per year |
| Annual Plan - 7 Days Trial | $89.99 | per year |
| 3 Day Trial - BookWatch Premium | $89.99 | per year |
| Annual Subscription Free trial | $99.99 | per year |
| 3 Day Trial - BookWatch Premium | $139.99 | per year |
| BookWatch Premium Free Trial Annual | $139.99 | per year |
| 7 Day Trial - Yearly Plan | $197.99 | per year |

**What reviewers like**

- 💡 Helpful for visual learners
- 👍 Convenient and easy to use
- 🚀 Time-saving summaries
- 👍 Great content and animated videos

**What reviewers complain about**

- 🐛 Inconsistent search functionality
- 🐛 Incomplete book access after subscription
- 🔒 Questionable subscription practices
- 🐛 Lack of English subtitles/captions

**Reported bugs**

- Intro content not fully accessible
- Subscription issues and lack of refunds

**Requested features**

- Background listening mode
- Web/desktop version
- Improved visualization


## Frequently asked questions

### Is Catalytic Converter Guide free?

Catalytic Converter Guide is free to download, with in-app purchases available.

### Is BookWatch free?

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

### Which has better reviews, Catalytic Converter Guide or BookWatch?

BookWatch is rated higher. Catalytic Converter Guide averages 3.6 out of 5 from 14 ratings, while BookWatch averages 4.7 from 14K ratings.

### Do Catalytic Converter Guide or BookWatch have ads?

BookWatch shows ads; Catalytic Converter Guide does not.

### Which is updated more often, Catalytic Converter Guide or BookWatch?

Catalytic Converter Guide ships an update every 3 days, and BookWatch every 3 days. Most recently, Catalytic Converter Guide was updated on October 24, 2026 and BookWatch on October 25, 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.*