Comparison

The Stack System vs Fiix Body

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

The Stack System

Enhance your golf game with science-based training modules for speed, wedging, and putting. Improve distance, accuracy, and consistency with personalized practice sessions and detailed analytics. Requires compatible hardware.

Highlights
  • Variable inertia speed training for distance
  • Science-based wedge distance control
  • Gamified putting practice and analytics
  • Personalized practice sessions
  • Real-time scoring and insights
  • Customizable training modes
Features
Read full description

The award-winning golf training app trusted by more than 75,000 golfers — built to help you hit longer drives, wedge it closer, make more putts, and understand your game like never before. STACK SPEED TRAINING Creates personalized training programs designed to help you swing faster and drive the ball farther. TheStack hardware is required. STACK STATS (NEW) Tracks your on-course performance and shows where you can improve. Identify strengths and weaknesses with advanced insights across every club, distance, lie, and more. STACK WEDGING Sharpens your distance control from 140 yards and in with gamified combines and real-time feedback powered by Stack Radar. PRACTICE TRACKER Elevates range sessions with structured full-swing practice and shot tracking for every club in your bag using Stack Radar. STACK PUTTING Combines intentional practice with data-driven analytics so you can test equipment, identify tendencies, and make more putts. LEARNING LIBRARY Access 60+ instructional videos from PGA Tour coach Dr. Sasho MacKenzie covering the key concepts, feels, and drills behind efficient swings and faster speeds. MEMBERSHIPS TheStack Premium Membership — $129/year Includes Stack Speed Training, Stack Stats, Stack Wedging, Practice Tracker, Stack Putting, and the Learning Library TheStack Speed Membership — $99/year Includes Stack Speed Training, Stack Wedging, Practice Tracker, Stack Putting, and the Learning Library TheStack Scoring Membership — $99/year Includes Stack Stats, Stack Wedging, Practice Tracker, Stack Putting, and the Learning Library Payment is charged to your Apple account after purchase. Subscriptions auto-renew unless canceled at least 24 hours before renewal. Any unused portion of a free trial is forfeited upon purchase. Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula

About

Fiix Body

This digital physical therapist guides you through elbow pain recovery at home. It provides personalized therapy schedules, tracks your progress with data and surveys, and offers helpful tips and videos to maximize your treatment experience.

Highlights
  • Personalized therapy schedules
  • Progress tracking and weekly scores
  • Pain assessment surveys
  • Comparison graphs with other users
  • Helpful tips and video guides
  • Push notification reminders
Features
Read full description

Your own digital physical therapist that keeps you on track! Fiixing your elbow pain at home with the Fiix Elbow device just got even easier with the Fiix App. The app tells you what to do, when to do it and tracks your success! CHOOSE YOUR THERAPY SCHEDULE Pick the days and times for your Fiix Elbow device sessions and exercise sessions, based on YOUR schedule and at YOUR convenience. Stay on track with push notifications to your smart phone or smart watch when it’s time for treatment. TRACK YOUR PROGRESS If you like data, you’ll love how the app tracks your progress so you can see how you’re doing every step of the way. You get scores each week measuring your adherence to the therapy program so you can celebrate your success. Plus, assess your pain with the weekly survey, and check out the graph that shows how you compare to others throughout the 10-week program. MAXIMIZE YOUR EXPERIENCE Take advantage of helpful tips and short videos at your fingertips to get the most out of your treatment. The Fiix App is here to support you every step of the way so you can get back to doing the activities you love without the elbow pain!

Screenshots

The Stack System4 screens
Fiix Body4 screens

Verdict

The call

The clearest difference is in-app purchases: Fiix Body at none against The Stack System's 8. Fiix Body also leads on device support (3 vs 1). The Stack System's advantage is review sentiment (86% vs 67%) and ratings volume (7K vs 297). On price, update cadence, ads and iOS requirement there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. The Stack System sells 6 in-app purchases, starting at $9.99 per 7 days. Fiix Body asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

The Stack System holds the better App Store score, 4.9 against 4.7. That said, the two scores are not equally well evidenced: The Stack System has 7K ratings behind it against 297, so its average is the more settled of the two. Written reviews point the same way: 86% of The Stack System's written reviews are positive against 67% of Fiix Body's.

UpkeepUpdate frequency

The Stack System ships an update monthly, Fiix Body every 5 weeks. The most recent releases landed on October 1, 2026 and June 9, 2026 respectively.

Scorecard7 real differences · 4 level
The Stack System versus Fiix Body: the parameters behind the verdict, then further details
ParameterThe Stack SystemFiix Body
PriceFreeFree
Rating4.9 (7K ratings) — better4.7 (297 ratings)
Positive reviews86.3% of reviews — better66.7% of reviews
Number of ratings7K — better297
Update frequencyMonthly — betterEvery 5 weeks
AdsNoNo
In-app purchasesYesNo — better
MonetizationFreemiumFree — better
Best chart rank#156 — better—
DevicesiPhoneiPhone, iPad, iPod — better
Requires iOS16.215.6 — better
Further details — not scored
Size213 MB33 MB
Age rating4+4+
DeveloperThe Stack System, LPFiix Body

Customer experience

The Stack System

All ratings7,009 ratings
Positive98.9%
Neutral0.8%
Negative0.3%
Written reviews139 reviews
Positive86.3%
Neutral6.5%
Negative7.2%

Fiix Body

All ratings297 ratings
Positive94.6%
Neutral3.7%
Negative1.7%
Written reviews6 reviews
Positive66.7%
Neutral16.7%
Negative16.7%

Bugs and requests

The Stack System

Reported bugs

2 issues
  • Putting app not working properly
  • Slope percentage input issue

Requested features

3 requests
  • Calendar integration
  • Music/podcast playback integration
  • Apple Watch support

Fiix Body

Not enough reviews yet to summarise bugs or requests.

In-app purchases

6 purchases

The Stack System

Subscriptions6
  • Stack Putting 1 Week$9.997 Days
  • Stack Putting 1 Wk$9.997 Days
  • TheStack Speed Training3 Days trial$14.997 Days
Show 3 more
  • TheStack Scoring Membership3 Months trial3 variants$99.001 Year
  • TheStack Speed Membership$99.001 Year
  • TheStack Premium Membership1 Year trial$129.001 Year
None

Fiix Body

No in-app purchases

Questions

Is The Stack System free?
The Stack System is free to download, with in-app purchases available.
Is Fiix Body free?
Fiix Body is free to download, with no in-app purchases.
Which has better reviews, The Stack System or Fiix Body?
The Stack System is rated higher. The Stack System averages 4.9 out of 5 from 7K ratings, while Fiix Body averages 4.7 from 297 ratings.
Do The Stack System or Fiix Body have ads?
Neither The Stack System nor Fiix Body shows ads.
Which is updated more often, The Stack System or Fiix Body?
The Stack System ships an update monthly, and Fiix Body every 5 weeks. Most recently, The Stack System was updated on October 1, 2026 and Fiix Body on June 9, 2026.

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