Actually, I have an update on this. Being the sick guy who has to try everything, I had to try this one as well, so yesterday I bought a subscription.
First impressions are the following:
- The section on tactics (the "gym") is really nothing special - ChessTempo is way better than that one, so I will just stick to it;
- There are a few sections, though, which I think are well worth the annual fee:
- How good is your chess? This one is very nice: you basically have a full game, in ChessBase training format, and you have to play as White or Black, trying to find the "best move" every time. Every move (both good and bad) is thoroughly commented, and you get points for each correctly guessed move (the better the move, the more the points). They are clearly putting a lot of effort in this, and I think the result is just plain great
- Your move? Another section, in the same format, for training tactics. You are given a position, and you have to find out what the best move is. Again, moves are very well commented
- Strategy Test: same technique as the above point, but this time it is about finding a strategic move that will resolve the game
On top of this, you have nice sections with articles on openings, middlegame, ending, but I would say the real differentiator is in the 3 points above. The fact that you can download them as ChessBase file, and build your own library, plus the fact that you can work on them offline, is really good.
In terms of community activity, it does not seem too high: there is a forum for all users, but with just very few posts over the last months.
Hope this helps.
Andre