Just finished my first (and probably only) playthrough, on Hardcore difficulty. It's actually pretty good entertainment
if you play it as an Action Adventure game and forget it's trying to be an RPG.
I was positive surprised by some of the quests and writing, and I loved that stuff changes depending on what you do or did in the earlier games. To give an example: in order to get the Salarians support the war effort, I had to sabotage the curing of the Genophage without the Krogans knowing. To do so I had to shoot Mordin in the back but thought it was worth it because I got both the Salarians and Krogans. Wrex found out my deception later in the game and I had to shoot him too and it was certainly something I didn't see coming. You also get to kill Anderson, Udina, the Illusive Man etc. and make other choices (such as give the Geth a free mind) although I'd have to play again to see if they have any real effect. Unfortunately there's also a ton of fedex quests where you just run around delivering items you found while scanning planets. If I had known the "war score" is useless I wouldn't have wasted my time doing those.
Combat is pretty good too although it gets a bit tedious in the end because there's much less variety in the enemies than in ME2. You'll be fighting either Cerberus troops or Reaper troops the whole time.
3/5