Just completed this, thoughts below:
+More of the same, usual strong storyline and characterisation
+Character models are good
+Decent framerate, 75-120fps throughout
+Learnt some technical lessons from ME2 – no uncrypted config file, able to change mouse sens in menu etc, and I only got stuck in the terrain once (inside the geth mainframe thingy where I managed to fall off the steps)
+Reasonable game length, took me ~28h
+War Fleet adds a bit of focus to your questing in terms of (seemingly) tangible rewards, although I'm not sure how much difference it actually made in the end
+Ending was better than expected
+Levels are generally well designed
-Side missions are very uninformative, using cluster/planet names inconsistently, not updating when you have obtained an quest item (so you have to check and remember what you’ve picked up during scanning etc)
-Side missions are too easily broken (or require a lot of lame linear backward and forwarding focussing on a single mission at a time to avoid the risk of them breaking). Good example would be when I got access to Tchunka, I had one main quest and two side quests available on the planet. So, rather than constantly travelling back and forth to the citadel, I tackle all three missions in succession (leaving the priority mission to last to try and avoid missing out on the side missions). Problem is, when I had done them all and returned to the citadel to ‘cash in my chips’, I discovered that the Citadel was under attack and I could no longer complete one of the sidemissions. I know this type of thing can happen in RPGs but it is highly frustrating.
-Aside from London, the texture quality is poor for a 2012 game, it’s all a bit 2008. VRAM usage stayed under 750MB throughout – smells like consolitus.
-The Citadel doesn’t feel as expansive as in ME1, they’ve tried to streamline it I guess but for example only having access to the Human embassy is disappointing
-New characters don’t feel quite as strong
-Only being able to use two teammates at once sucks, seems a bit pointless amassing this big crew and then only going in a team of three, especially on the final push. I don't think I ever used James, EDI or Liana unless I had to.
-Few continuity holes, no idea how someone in my squad for the final mission were able to make it back onto the Normandy in time for the end cutscene (especially considering according to radio chatter they were all wiped out)
-The whole Paragon/Renegade thing seems a bit underused, I still don't really understand what affect it has on things other than giving you the odd mouse click in cutscenes or conversation options (which I nearly always have both options anyway)