My main gripe with this is that the AI opponents all seem to play in the same way regardless of their "personalities". And none of them are at all difficult to beat, even for a novice player who isn't giving the game their full attention.
It offers a fair range of expansions but not nearly so many as the iOS app and most of them are slightly buggy, especially around farm scoring. It isn't worth paying the extra money for these in my opinion, although I won't deny that, bugs aside, they're implemented quite well and do add to the playing experience.
Overall, I do play it every now and again and it's a reasonable way to waste 20 minutes or so. It's cheap too (if you're happy to stick to the basic game), which makes it quite difficult to resist for most people.