I mean, it's a great game. Finished it singleplayer with a completely new character (i.e. I didn't start in veteran mode) in like 16 hours I believe, but I did not find all the secrets. Started veteran and I'm still having fun with slightly harder enemies and - of course - better SHINIES. Hopefully I won't miss things this time.
The story was fine, although a few things were predictable, but I didn't mind. OST is great
, Katarina is awesome again - although I'd wish for a few new lines instead of those we already know from VH1 (mainly talking about her reactions to "send to town"). Also perhaps different voice packs for different class (you have three to choose from). But still, I can't complain much about the visuals nor sound (some monsters sound stupid when they get hit repeatedly, but whatever). VH2 also has several new features compared to VH1, mainly Chimera (I'm not gonna spoil it, but it's a fun thing) and generals (or whatever they were called, those guys you send out to do missions). And the tower defense minigame is back (this time we have 6 different levels).
The only thing I fear about is multiplayer, since I've heard that there are still MP bugs, similar to those VH1 had. However, as I haven't played MP yet, I'm only mentioning things I've read on the forums - nothing I've experienced myself. I did have some trouble with VH1 multiplayer, though...
Did I mention the OST and Katarina are great? No? Well, OST and Katarina are great.
tl;dr: Buy it if you like aRPGs.
EDIT: So, I now had a chance to play multiplayer. In fact, went through the whole first playthrough with a friend and on the veteran one now. Yes, this game still has some glitches, but not even half as bad as VH1. No more incredible, random lags during any dialogue. I (as a non-host) did crash a few times, maybe thrice during that one playthrough. There are other glitches such as "invulnerability bubbles" staying on champions despite them being vulnerable (you can see their HP go down, though, so that's a clear indication they're not immortal ;-)), had some (mostly allied) characters keep running into a wall, etc. But the gameplay is smooth and frankly - I'd say that considering my friend's laggy connection (he lags on TeamSpeak!) this game somehow manages to workaround those lags well. Well, that's if you get used to the fact that each of your hit is slightly delayed, but that's not a problem after you play for a bit. I don't even pay attention to that anymore.
So, yes, this is still "thumbs up" and still "definitely recommended".