Comparison

Opus One vs CheckOn

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

Head to head
About

Opus One

This app helps you manage tasks and notes with a paperlike interface. Organize your day with daily task lists, schedules, and notes, and use a master task section to capture all your to-dos. Features include drag-and-drop reordering, event integration, and customizable notes.

Highlights
  • Master Task section
  • Daily Task lists with status, priority, and notes
  • Daily Schedule and Event integration
  • Daily Notes with customizable text formatting
  • Drag and drop task reordering
  • Cloud synchronization
  • Sketch drawing canvas
Features
Read full description

Opus One is a real day planner, not another to-do app. Each day gets its own page — tasks with A/B/C priorities, your schedule, and notes — on a planner that looks and feels like paper. Plan on iPhone, iPad, and Mac, and it all stays in sync. YOUR DAY ON ONE PAGE • Daily Tasks with A/B/C priorities, status, notes, and alarms. • A schedule that shows your Calendar events alongside your tasks. • Drag a task onto the schedule — with task durations, the end time fills in automatically. • Daily Notes with photos, PDFs, checklists, and audio. • Today's weather and a daily quote, right on the page. PLAN BEYOND TODAY • Master Tasks: everything on your mind in one list, no due date required. • Goals with timelines, photos, and progress you can see. • Roles: review the areas of your life each week so nothing important gets crowded out. • Mission, Values, and Vision pages to keep the big picture one tap away. • Meeting Planner for agendas, decisions, and next steps. NOTES AND JOURNALS • Rich notes with fonts, colors, tags, and your own custom sections. • Sketch and handwrite with Apple Pencil. • Journals with 25 covers to choose from, plus a guided Gratitude Journal. IT GOES WHERE YOU GO • Home Screen widgets for today's tasks, your mission, your values, and daily quotes. • Live Activities keep today's tasks on your Lock Screen. • Add a task from Control Center, or ask Siri. • Apple Watch app to see your day and check off tasks from your wrist. • iCloud sync across iPhone, iPad, and Mac. MAKE IT YOURS • Planner themes, including seasonal ones. • Task-complete sounds and rewards for finishing what you planned. • Color-coded categories and repeating rules with advanced options. OPUS ONE PRO The core planner is free. Opus One Pro adds cloud sync across all your devices, weather, attachments (images, PDFs, audio), Apple Pencil sketching, categories, repeating rules, Goals, Siri, and themes. One subscription covers iPhone, iPad, and Mac on the same iCloud account. Available yearly or monthly. Subscription details: Payment is charged to your Apple Account at confirmation of purchase. The subscription renews automatically unless auto-renew is turned off at least 24 hours before the end of the current period, and your account is charged for renewal within 24 hours before the period ends. Manage or cancel in your Account Settings. Privacy Policy: https://piso13.com/privacy-policy-2/ Terms of Service: https://piso13.com/terms-of-service/

About

CheckOn

Features
Read full description

Aplicación CheckOn para rastreo satelital. envio de comandos, consultas de historial, recorrido en tiempo real, panel de eventos, Iniciar Sesión con ID, notificaciones push.

Screenshots

Opus One4 screens
CheckOn4 screens

Verdict

The call

The clearest difference is in-app purchases: CheckOn at none against Opus One's 2. CheckOn also leads on iOS requirement (12.0 vs 15.0). Opus One's advantage is update cadence (every 3 weeks vs every 16 months). On price, ads and device support 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. Opus One sells 2 in-app purchases, starting at $4.99 per month. CheckOn asks for nothing beyond the download.

UpkeepUpdate frequency

Opus One ships an update every 3 weeks, CheckOn every 16 months. The most recent releases landed on October 18, 2026 and October 7, 2026 respectively.

Scorecard3 real differences · 7 level
Opus One versus CheckOn: the parameters behind the verdict, then further details
ParameterOpus OneCheckOn
PriceFreeFree
Rating4.7 (973 ratings) — better—
Positive reviews65.7% of reviews—
Number of ratings973 — better—
Update frequencyEvery 3 weeks — betterEvery 16 months
AdsNoNo
In-app purchasesYesNo — better
MonetizationSubscription—
DevicesiPhone, iPad, iPod, Apple Watch — betteriPhone, iPad, iPod
Requires iOS15.012.0 — better
Further details — not scored
Size187 MB10 MB
Age rating4+4+
DeveloperPISO 13, Inc.hernando oviedo

Bugs and requests

Opus One

Reported bugs

4 issues
  • Sync issues between devices
  • App crashes and data loss
  • Keyboard not working on iPad
  • Distorted font in calendar view

Requested features

6 requests
  • Add weekly and monthly views
  • Improve Apple Pencil support
  • Add project management features
  • Integrate with more calendar/task apps
  • Provide better training and tutorials
Show 1 more
  • Allow customization of UI and themes

CheckOn

Not enough reviews yet to summarise bugs or requests.

In-app purchases

2 purchases

Opus One

Subscriptions2
  • Opus One Pro7 Days trial$4.991 Month
  • Opus One Professional7 Days trial$39.991 Year
None

CheckOn

No in-app purchases

Questions

Is Opus One free?
Opus One is free to download, with in-app purchases available.
Is CheckOn free?
CheckOn is free to download, with no in-app purchases.
Do Opus One or CheckOn have ads?
Neither Opus One nor CheckOn shows ads.
Which is updated more often, Opus One or CheckOn?
Opus One ships an update every 3 weeks, and CheckOn every 16 months. Most recently, Opus One was updated on October 18, 2026 and CheckOn on October 7, 2026.

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