After a lot of hype in my friend circle and with a free Sunday evening, I hopped on the train and pre-ordered to join the early beta.
I played a (frost) sorcerer up to level 22, completed the main quest and also a handful of side quests, and have to concur that the general impression is good. I'm still not big on the shared world part, but since it's mostly noticeable in cities, it's mostly an inconvenience.
Atmosphere and music were fine, although I feel they are overcompensating a bit w.r.t. blood, gore and dead bodies on spikes.
Based on impressions from the first act, I would say that the storytelling and dialogs are not exactly great, but it's not nearly as bad as Diablo 3. We'll have to see how things develop in later acts, though.
Visuals are generally good and frame rates were smooth for me, except for cities, but that might be a server issue (it good noticeably more pronounced when people people were flocking in for the last hours yesterday afternoon). I would prefer the zoom factor to be a bit smaller, but I guess they want some of their enemies to really fill most of the screen.
Gameplay is fine and was fun for most of the roughly 8 hours I played. I have heard from people playing barbarians that those were less fun, but for my sorcerer the challenge level felt fine. Spells are solid, though only frost nova felt like it had real punch (blizzard felt weaker than it was; frost armor and ice blades were ok). Controls are good with an XBox controller - I hear some complaints from people playing with mouse and keyboard, though. Evading attacks is definitely recommended if you don't want to get smashed by very large hammers, cleaved by equally sized axes or pierced by slightly smaller swords. The one thing I'm not fully sold on is your environment auto-leveling with you. So a) even if you later go back to the starting area, you are challenged just like you were when you cleared that area first time and don't mop the floor with your enemies, and b) you might be level 20, but see a level 5 character hitting enemies harder than you.
All in all, I look forward to play this game with friends when it comes out in summer. I don't think it will end up occupying the same spot in my gaming heart as the first two parts, but it looks like this is going to be a fun game.