As you can see, I don't have premium membership, so I don't know, but I saw someone say there are puzzles where you simply take a hanging piece. Those "puzzles" are a waste of time IMO. However it may be only very low rated problems, and it wouldn't be an issue for most people (?)
Also the puzzles are timed on chess.com... which has its uses sure, but I prefer untimed puzzles so there's no pressure to guess.
The "other resource" is probably chesstempo.com, which is great, but I also have books and an old version CT-ART. I like books because they're available anywhere, but the digital puzzles (both on my computer and online) are more organized (you can review missed problems easily) and for quickly checking variations (e.g. with an engine).
How good is the tactics trainer on this site for improving chess tactics? Should I be using something else instead, and if so, specifically why? I hear mention of other resources, but no one explains why the others are better. Is it just that they are free?