I downloaded the Dragon Age II demo and played it to its fairly quick conclusion.  I played as a sarcastic female warrior using 2H weapons and then played as a goody goody male dw rogue.  The former, I played without ever pausing or switching between characters.  The latter I played the exact opposite: I switched around a lot and paused frequently to issue commands.  Note that inventory and character appearance were locked.  I looked, but was unable to interact with anything so I couldn't gleam anything.
 
Quick things: Graphics are good, but I still hate the hurlock redesign.  I hope some modder is already planning on a reskin.  Voice acting sounds good enough.  I had no technical problems.  Load times popped up quite a bit but I expect that sort of thing from a demo.
 
The personality stuff works as advertised.  After a few quips Hawke stuck to the usual answers I was giving.  They were minor differences.  "I was trying to talk him down" versus "Stab first and ask questions later?" after Isabela started a fight in the last bit of the demo, for example.  The dialogue wheel with the intentions in the center circle work well.  The only question I have is what do all those mean?  A laughing mask is sarcastic / comical and an angel means goody goody, but what the hell does a diamond mean?  Still, only one or two left to the imagination will sort themselves out eventually.
 
One change I noted that I do not like is the inability to center AoE spells on a target.  Instead, you target the area and if the target(s) is / are no longer there, then tough luck.  On the flip side, this also works in your favor, as you can now dodge moves by not being in the line of fire.  I recall many times in Origins where if I had been in the way when something was cast / initiated, but  moved out of the way, then you would still get hit.  Glad to see that's corrected, but I would very much like to set my mage to center a fireball on an ogre, rather than just make my best guess as to where it's going to be.  Maybe I was missing something but I absolutely could not get it to lock on to a target, only an area.
 
One of BioWare's talking points is that there is no longer a single linear progression to character abilities.  First of all, this was not entirely true in Origins, as you could mix and match and only had to go through some skills to get to the good ones.  The system is essentially unchanged in Dragon Age II and only looks different.  Yeah, they made it a web instead of 3-4 linear paths.  However, when you look at it, each skill requires a certain level and sometimes a prerequisite number of skills learned in that skill group.  So even though you may have a "path" unlocked, you are still level-locked.  If you stick to a single group of skills, then you would be even more linear than Origins.  All of the customization would come from picking up the different ability groups and specializations so you could mix and match what you do at what levels.  But then again, how is that different from Origins?  Oh right, you can "upgrade" a skill.  Again, some skills had upgrades in Origins.  The next skill in line after Shield Defense removed the SD attack penalty, for example.  Secondly, these also have level restrictions.  So even though you know a skill, it may be a couple levels before you can upgrade it and then you're not so much choosing an upgrade over a new skill as you may be locked into that decision due to level restrictions.  I'm not saying this is a bad system, but with what they showed in the demo, it's not nearly as different from Origins or as robust as they have thus far claimed.
 
As for battle, mages can now attack with their staff.  Good, although spells are obviously better.  The rogue was a lot more fragile than its Origins counterpart and didn't move like the warrior.  The warrior could withstand far more punishment than the rogue, which is a nice way to differentiate the two classes.  Single-clicking a target made you auto-attack and there was of course the hot bar that you could launch special moves from.  You do NOT have to keep clicking to attack.  However, I found that after some moves that knocked down / away foes, you'd stop auto-attacking and would have to re-click the target.  That step is a tad annoying when you are trying to finish off an opponent.  Maybe I knocked them down in order to save myself from a little damage and was not necessarily aiming for crowd control.
 
The battles were a lot faster-paced and not necessarily tactical.  The only battle I had issue with was the ogre during my very first attempt in a no-pause run through.  And that was mostly due to me not paying attention to adds and getting wiped by the ogre.  I ended up kiting it around with Hawke's sister (mage) and whenever it stopped, launching a fireball at (hopefully) its location.  When I knew what I was doing my second time around, pausing was largely unnecessary as my tank's tactics were good, as were my mage's.  So I remain so far unconvinced that there are battles that MUST be played tactically or that it's any easier.  That is a disappointment.
 
The story was on fast-forward, obviously, but what I saw was on par with the BioWare usual, for good or bad.  I hope that the full game will explain things more and make better transitions, but we'll see.  So is it good?  I suppose you could say that.  It is only a tiny fraction of what the whole game probably is.  Is it the next biggest and best thing out there and will wow everyone like Origins did? Uh, no.  Not if you're looking for more rpg and less fast-paced combat with rpg elements.  If you're the type who doesn't particularly care for complexity in your rpg and would love something bordering on action rpg territory, then you'll probably like DA2.