# VibraUnits vs PE Prep Pro

The clearest difference is review sentiment: VibraUnits at 88% against PE Prep Pro's 0%. VibraUnits also leads on price (Free vs $34.99) and rating (4.6 vs 1.7). PE Prep Pro's advantage is update cadence (every 3 weeks vs every 10 months). On ads, in-app purchases and device support there is nothing between them.

VibraUnits is free to download; PE Prep Pro costs $34.99 up front. Neither carries in-app purchases, so what you see is what you pay.

VibraUnits holds the better App Store score, 4.6 against 1.7. Both are backed by a comparable volume of ratings — 9 and 3 respectively. Written reviews point the same way: 88% of VibraUnits's written reviews are positive against 0% of PE Prep Pro's.

VibraUnits ships an update every 10 months, PE Prep Pro every 3 weeks. The most recent releases landed on November 1, 2026 and November 5, 2026 respectively.

## The numbers

| Metric | VibraUnits | PE Prep Pro |
| --- | --- | --- |
| Price | **Free** | $34.99 |
| Rating | **[4.6 (9 ratings)](https://appshunter.io/ios/app/vibraunits/id445231670/reviews)** | [1.7 (3 ratings)](https://appshunter.io/ios/app/pe-prep-pro/id6746470072/reviews) |
| Number of ratings | **9** | 3 |
| Positive reviews | **87.5% of reviews** | 0.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 10 months | **Every 3 weeks** |
| Monetization | **Free** | Paid |
| Size | 8 MB | 43 MB |
| Requires iOS | **7.0** | 15.1 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | +4 | +4 |
| Developer | [Motionics LLC](https://appshunter.io/developer/424498959) | [Examp, LLC](https://appshunter.io/developer/1479303574) |

## What reviewers say

### VibraUnits

[App page](https://appshunter.io/ios/app/vibraunits/id445231670)

This application facilitates the conversion of mechanical vibration analysis units. It supports conversions between displacement, velocity, and acceleration, along with frequency and various amplitude scales.

**Highlights:** Velocity, acceleration, displacement conversion, Frequency conversion (Hz to CPM), Displacement conversion (mils to microns), Velocity conversion (inch/s to mm/s), Acceleration conversion (G's to m/s^2)

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

**In-app purchases:** none


### PE Prep Pro

[App page](https://appshunter.io/ios/app/pe-prep-pro/id6746470072)

This comprehensive exam preparation system offers over 1,400 realistic practice questions across 16 engineering disciplines. It provides detailed performance analytics to pinpoint weak areas and includes essential code summaries for offline study.

**Highlights:** 1,400+ realistic exam questions, 16 major engineering disciplines, Performance analytics, Offline functionality, Essential code summaries

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

**In-app purchases:** none


## Frequently asked questions

### Is VibraUnits free?

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

### Is PE Prep Pro free?

PE Prep Pro costs $34.99, with no in-app purchases.

### Which has better reviews, VibraUnits or PE Prep Pro?

VibraUnits is rated higher. VibraUnits averages 4.6 out of 5 from 9 ratings, while PE Prep Pro averages 1.7 from 3 ratings.

### Do VibraUnits or PE Prep Pro have ads?

Neither VibraUnits nor PE Prep Pro shows ads.

### Which is updated more often, VibraUnits or PE Prep Pro?

VibraUnits ships an update every 10 months, and PE Prep Pro every 3 weeks. Most recently, VibraUnits was updated on November 1, 2026 and PE Prep Pro on November 5, 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.*