Great game! Loved the ending (for scifi lovers).
The weak central story issue in ME2 is not an issue here. The story is focused, intricate, plausible, and enjoyable. The companions do not dominate and take precedence over the central character, as in ME2, thankfully.
The graphic vistas in ME2, while impressive, never seemed connected to the player. Also not an issue here. They did a great job making Shepard seem part of the fantastic world. A superb job, really.
The music perhaps does not quite match the immersiveness of ME1, but it comes close. Loved the voice acting in all 3 games.
The horrible mini-game from ME2 is absent, thankfully. What we have instead is rather simple, completely optional, and it's fine for what it is. The Mako in ME1 was better, so this is a little bit of a let down, but also a relief that the tedium from ME2 is not repeated.
The weakness of this kind of interactive story is that your decisions can never have much impact on the game (they are not going to create a whole series of quests and worlds which you will never visit based on one decision you made). But nevertheless, they did an admirable job of trying to mitigate that issue. Unfortunately, you can't experience a lot of the content unless you completed the ealier games. That's sort of okay except that it detracts from replay valule.
The ending, appropriately, has different options. The results are not concrete and somewhat ambiguous, and many people are not happy with that. But I had no issue with it at all. Reminds me of how much more I liked the ending in Blade Runner Director's Cut rather than the theater release.
One thing that holds this game back somewhat is the console-friendly interface. I understand they make the game so it can run the same on consoles, but that's letdown for the much more versatile PC. I should have had separate keys for the different actions, rather having space bar be take-cover/activate/run/climb all in one. I should have had a continuous run forward key. I should have been able to press J to bring up the journal rather than going through menu's. I don't think it would have taken too much effort to make these things happen. Yet all this does not spoil the game--only weaken it slightly.
I do really miss is the ability to explore worlds, as in ME1. However, ME1 did not do this as well as it could have. There were too many generic environments, and there weren't enough interesting things to find while exploring. Even so, I miss it, and this game would have been better for it.
Worst thing about the game: replay value is rather low. It's a very linear story, and many of the options are dependent upon having characters and their decisions from ealier games. For this reason, I still think ME1 was the best of the trilogy overall.