There are some connection errors. I didn't notice them until recently though so I'm not sure whether it's my connection or the games fault.
In any case, you would probably be better off checking out Silent Hill: Book of Memories. It's supposed to be a superior dungeon crawler. I have it on my shelf but I haven't played it yet. At least look into it before you make a decision.
No no no. Silent Hill : Book of Memories is a really bad game. Dungeon Hunter is much better then this. Book of Memories has 1 "dungeon" with 100 floors, the game itself is slow and very repetitive, not just the gameplay, but also the maps. They all look the same. Random or not, its not good.
If you really want a good ARPG, play DH or Ragnarok.
Online Mode is fine, im still playing it without connection errors.