Originally Posted by Do it Right
I only have a free account there which offers like 3 problems/day so it's been tough to get a handle on what their more challenging problems are like. They also have that very slow rating system on the tactics problems and with 3problems/day I'm still getting silly trivial stuff.
At least on the iOS app you can log out from your account and log in again as a guest - then you'll be allowed to do 100 tactics puzzles. Can't remember if it rates you when you play as an unregistered guest, but at least you'll get a feel for the puzzles.