I didn't really hit any issues with odd facial expressions etc. Not always the greatest animation ever, but not off-putting. I had the trying to run upstairs glitch and a few minor clipping issues, but on the whole it was fine. Graphics were frequently gorgeous. (I am playing on a reasonable high-spec PC, and it seems like there were more issues on other platforms.)
I love the new combat and Mako (I mean, Nomad). Jetpacks and the more fluid cover are great. Haring around the planets in the Nomad tweaks all the right nostalgia notes from the first game (which for all its flaws might still be my favourite), but with more going on. I felt like they struck the right balance between number of planets and amount of content per planet (compared to the original's one quest at best and a couple of points of interest on dozens of random planets). Also, I love the gun augmentation that brings back the original's ammo system.
This is possibly a minor spoiler if you're less than about half way through the game, and also includes spoilers for the original trilogy:
Mind you, one of my complaints about 2 and 3 is that they never really came close to replicating how well 1's Saren/Sovereign villain duo worked. Maybe the Archon is an attempt to return to having a human (or, well, alien) face on the bad guys, but where Saren was ultimately a relatable, tragic figure, the Archon is just a generic personality-free world-domination type who could have walked off the set of the latest Marvel movie.
Writing had some wobbles too (see spoilered section), but I thought it at worst did the job, and as ever with Bioware games was at its best with some flashes of brilliance with the character writing. I ended up liking Peebee, much to my surprise, and Drack in particular is awesome. In random side characters, Sloane provides some unexpectedly hilarious moments too (pro tip: be overly familiar with her).
Some of the binary choices felt a bit more forced than usual. Case study (minor spoilers for one side quest):
I like the new dialogue flavours. More flexibility than the paragon/renegade system.
The UX design is atrocious even by Mass Effect standards. What were they thinking?
The lame soundtrack really disappointed me. The Mass Effect 1 soundtrack is one of my favourite video game soundtracks (I have it on CD!), and I loved the soundtrack from 3 as well.
Upshot: It has its flaws for sure, but I definitely enjoyed sinking 65 hours into it, will play the inevitable DLC, and look forward to the inevitable sequel.