Every time an action RPG is released, it's compared to Diablo 2. And every time, it fails the comparison... until now.
Torchlight 2 does this with great success. It doesn't have the most polished UI or graphics, nor the best storytelling, but there is just something that grabs you when you figure out how to maximise your character's efficiency, when you figure out a new strategy or mechanic, or when you sort through the loot after bringing a boss down with your friends.
Talking about loot, the items are varied, useful in many ways and, in the case of uniques and legendaries, show at least some creativity. They might not be perfectly balanced, but Torchlight 2 doesn't even try to convince you it's perfectly balanced: you can even switch to an easier difficulty if you want to, while getting the same level of loot! The important thing is, yo won't notice these imbalances unless you almost look for them. While playing with your friends, everybody is going to find fun loot, an interesting build, and be a useful part of the team.
Torchlight really makes a statement with its complex skill trees that are fun to explore and discover. If you are the least bit perfectionist, you WILL start over at least once after figuring out a better way to build your character. And you won't feel bad about it!
That's partly because, while being very classic, the environments are vast and diversified enough that you don't get bored quickly passing through them. More than once, I smiled thinking about whoever might have stretched his brain to create the enemies in the game. Most areas will have you rethink your strategy because of some cleverly designed monster on your way.
All in all, I can't believe such a good game would be available for only 20$. Is it perfect? No. Before you put a point into it, you can't predict what a spell does when leveled up higher than the first level. The absence of a real map screen is somewhat annoying, the voices are dull and lifeless and the game doesn't do much to get you involved in the storyline.
Still, I can't imagine anyone who wouldn't recommend this game after going through it once.