# e vs Subsurface Maps Offline

The clearest difference is monetization model: Subsurface Maps Offline at free against e's ad-supported. Subsurface Maps Offline also leads on update cadence (every 4 weeks vs every 2 months). On price, rating, ratings volume and ads there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

On the App Store both sit at effectively the same score — 5.0 for e against 5.0 for Subsurface Maps Offline. Both are backed by a comparable volume of ratings — 3 and 2 respectively.

e ships an update every 2 months, Subsurface Maps Offline every 4 weeks. The most recent releases landed on September 19, 2026 and September 16, 2026 respectively.

## The numbers

| Metric | e | Subsurface Maps Offline |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [5.0 (3 ratings)](https://appshunter.io/ios/app/e-sens/id1585074022/reviews) | [5.0 (2 ratings)](https://appshunter.io/ios/app/subsurface-maps-offline/id6654924764/reviews) |
| Number of ratings | **3** | 2 |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 4 weeks** |
| Monetization | Ad-supported | **Free** |
| Size | 32 MB | 81 MB |
| Requires iOS | 15.6 | **15.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [e-sens, Inc.](https://appshunter.io/developer/1479061797) | [Ben Hill](https://appshunter.io/developer/1645876200) |

## What reviewers say

### e

[App page](https://appshunter.io/ios/app/e-sens/id1585074022)

This tool allows water quality professionals to collect, manage, analyze, and track water quality test parameters. It is designed for water treatment facilities and professionals in the field.

**Highlights:** Water quality data collection, Data management, Analysis of test parameters, Tracking of water quality, Designed for professionals, Supports water treatment facilities

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

**In-app purchases:** none


### Subsurface Maps Offline

[App page](https://appshunter.io/ios/app/subsurface-maps-offline/id6654924764)

Access and edit your maps offline on your iOS device. Download maps from the cloud, make changes, and mark new points. Sync your edits back to the cloud for team access.

**Highlights:** Download maps for offline use, View and edit map features, Mark new points, Sync changes to the cloud, Turn map layers on/off

**In-app purchases:** none


## Frequently asked questions

### Is e free?

e is free to download, with no in-app purchases.

### Is Subsurface Maps Offline free?

Subsurface Maps Offline is free to download, with no in-app purchases.

### Which has better reviews, e or Subsurface Maps Offline?

e and Subsurface Maps Offline are both rated 5.0 out of 5 on the App Store, from 3 and 2 ratings respectively.

### Do e or Subsurface Maps Offline have ads?

Neither e nor Subsurface Maps Offline shows ads.

### Which is updated more often, e or Subsurface Maps Offline?

e ships an update every 2 months, and Subsurface Maps Offline every 4 weeks. Most recently, e was updated on September 19, 2026 and Subsurface Maps Offline on September 16, 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.*