# 421Grid vs RDM Playalongs

The clearest difference is price: RDM Playalongs at Free against 421Grid's $1.99. RDM Playalongs also leads on update cadence (every 3 days vs every 3 months) and iOS requirement (15.0 vs 18.0). 421Grid's advantage is in-app purchases (none vs 1). On ads and device support there is nothing between them.

RDM Playalongs is free to download; 421Grid costs $1.99 up front. RDM Playalongs sells 1 in-app purchase, starting at $12.99 per month. 421Grid asks for nothing beyond the download.

421Grid ships an update every 3 months, RDM Playalongs every 3 days. The most recent releases landed on October 15, 2026 and October 19, 2026 respectively.

## The numbers

| Metric | 421Grid | RDM Playalongs |
| --- | --- | --- |
| Price | $1.99 | **Free** |
| Rating | — | **[5.0 (10 ratings)](https://appshunter.io/ios/app/rdm-playalongs/id6802166294/reviews)** |
| Number of ratings | — | **10** |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 3 months | **Every 3 days** |
| Monetization | — | Free with in-app purchases |
| Size | 4 MB | 17 MB |
| Requires iOS | 18.0 | **15.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [N. Wheeler](https://appshunter.io/developer/312350021) | [Anthony Steller](https://appshunter.io/developer/6802166506) |

## What reviewers say

### 421Grid

[App page](https://appshunter.io/ios/app/421grid/id1598461370)

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

**In-app purchases:** none


### RDM Playalongs

[App page](https://appshunter.io/ios/app/rdm-playalongs/id6802166294)

This app offers three practice tools for drummers, including a metronome with advanced features, a sight-reading generator, and a library of exercises. It helps improve hand speed, accuracy, and reading skills with customizable tempos and rhythms. Track your practice time and engage with a community for support.

**Highlights:** 500+ practice exercises, Customizable metronome with unique subdivisions, Generates unique sight-reading exercises, Tempo control with range and climbing options, Practice time tracking and streaks, Community support from developer

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| RDM Playalongs | $12.99 | per month |


## Frequently asked questions

### Is 421Grid free?

421Grid costs $1.99, with no in-app purchases.

### Is RDM Playalongs free?

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

### Do 421Grid or RDM Playalongs have ads?

Neither 421Grid nor RDM Playalongs shows ads.

### Which is updated more often, 421Grid or RDM Playalongs?

421Grid ships an update every 3 months, and RDM Playalongs every 3 days. Most recently, 421Grid was updated on October 15, 2026 and RDM Playalongs on October 19, 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.*