I can't say for sure if it was the launch of Office for iPad that drove Google to move Sheets and Docs apps into the App Store. Previously the apps were built into the Google Drive app, and it doesn't appear that anything else has been changed about Sheets outside of the file handling. Sadly, Sheets has always been the weakest part of the online suite. The iOS version is even weaker. Though it would be easy to peg it against Excel, it might be more of a fair comparison to use Numbers. Numbers is also free, and lacks the power user features in Excel. Sheets lacks a formula picker, custom keyboard layouts for different data types, and there aren't any tools for charts.

Sheets needs better features to be useful. The collaboration tools are still the only features that puts Google's offerings ahead of Numbers and Excel. You can have multiple people working on Sheets at the same time, which is much better than the share and track changes method the other apps rely on. I am not really sure why these apps exist except for brand reinforcement. Drive once handled Sheets, but now when you open Sheets in Drive, you're sent to this new app. It's a mess.

What's Good: Still better collaboration tools than other office apps.

What Sucks: Missing a lot of essential features for editing spreadsheets.

Buy it?: You use Sheets if you have a spreadsheet you need to share with a lot of people, or you need to work closely with collaborators. Sheets is free on the App Store.