5 stars: One of the best app to train openings, endgames and tactics. Interface can be a little bit cryptic, especially for openings but once you get used to it, there's nothing better on the market. Tactics are a strong point here, because they tend to emulate real positions, so it's not always about mate in 3 or 4, but sometimes doing the only move that takes you out of the danger.
4 stars: Very useful for tactical training. I wish I could track my rating for online games i played via a chart or table based on categories (eg blitz 1600, standard 1650 etc). I couldn't access my online game records too. I hope it's not limited to premium membership.
5 stars: Imho the design is very old fashioned. But the content is top notch!
4 stars: Quite Good, the Controls Need Improvement, some work is needed with the interface too.
3 stars: I've installed it for the opening training, and it won't open!
5 stars: I love the commentary analysis plz make an offline app with the commentary analysis
3 stars: I am a big fan of running through tactics, but the latest update completely broke the app for me. Problem sets are no longer available, the game just hangs on both data and WiFi in multiple locations (in any mode beyond the menu). I have tried clearing cache and data as well as rebooting my phone. This was my most used app, but now it's basically useless unfortunately.
3 stars: There are even 2 buttons for 'opening training', but I can't figure out how they work...