I'll just paste what i wrote on neogaf ;p
Oh and optimization sucks hard in this game.
After testing 3 chars i was interested in, i can finally summary my 'experience'.
First of all classes were amazing to play. I've started with Wizard and really loved how powerful it is, i liked most skills a lot, but i think it was the most repetitive/boring class from all i've played, its of course only beta issue, because there are no runes, slots/skills are limited [we dont have in beta any movement skill, which sucks ;p]
Then i played Monk, who i gave two/three items i found with first run of Wizard and to make game 'a little harder' i havent changed them almost for an entire game. Monk became really fun when he gets Deadly Reach. Skill is not only fun and well balanced, but also gives You spirit that You can use on other skills and make some combos I liked that a lot, even though this class was the weakest one. I didnt like Crippling Wave and You can even see that in movies below when i test it ;p Also it was the only class which needed to play fight Skeleton King 'safe'.
Last one was Demon Hunter that i didnt like at first, it was slow, skills were quite crappy, hatred ended too fast etc, but thats changing after level 5-6 and it gets better and betters when You level up. It was probably the easiest class for killing Skeleton King, because had really strong ranged attacks and awesome dodge. Dodge is awesome [its called Vault as i recall] and i'm quite unhappy that i cant use it to travel non stop
You can watch my full Demon Hunter run on youtube [link below]
Gameplay is really fun and addictive, even though beta is easy as fuck ;p [i cant believe that some people on Blizzard board write that it was too hard o_0], but i can see how good it will be in higher difficulties with those all options. I really liked how responsive skills were and how could You easily combine them.
I liked physics, but i think for some it could be too overdone. Maybe its only a beta issue, but i think they focused on that too much [i'm ok with that because i love all physic stuff in games ]
I didnt like health orbs, they seem too random in the beta. I dont how they scales up on higher levels/difficulties, but i think that flask system in PoE is better designed and more predictable.
Crafting seem quite good, i havent leveled my Blacksmith yet [i'll do it today], but from i saw, items he crafts are useful and salvaging helps cleaning Your inventory, it will also be quite good currency later in game. I just hope it scales up well to Inferno.
Stash is too small, like almost none ;\ It should at least has 6+ pages.
Videos:
Wizard [just running around]
http://www.youtube.com/watch?v=UIuQIzcBjLg&hd=1
Monk [from Templar to Skeleton King]
http://www.youtube.com/watch?v=3irFzbt-6_k&hd=1
Demon Hunter [full run]
http://www.youtube.com/watch?v=h-qGi_mSR_I&hd=1
Oh and optimization sucks hard in this game.