Alright, I've got quite a few hours into ME now and I've gotta say, its a great RPG. I haven't been this into an RPG since FF7... even Oblivion didn't grab me like this one did.
BUT... all is not sunshine and puppy dogs. I understand when creating an entire universe to traverse, you're going to have to cut some corners... but making every single planet you land on the exact same with different lighting, weather effects, and possible extreme conditions, is just a little TOO lazy. At least the story of WHY you're on the planet is well thought out.
Tons of RPGs have world maps to walk around, but at least you do things on them... this, you just roam around, every once in a while coming upon some minerals or some sand creature, and hit 3 points of interest, then leave.  Even mines that I've been in were exactly the same in layout. There were made by different people on different planets, why are they exactly the same?  The Mako isn't terrible to control, but its basically just a way to extend the length of the game.
Secondly, the inventory is such garbage. I know how it works, but it still is a pain in the butt to use.
Thirdly, I'm not a fan of how the squad controls work in general, but more specifically I think they could have done a little bit better of a job with the way characters use their abilities. Perhaps its because I'm a soldier, but I rarely go into that menu at all during the fights.  I'm not even sure if the AI of the squad is smart enough to use their abilities without me telling them to.  This isn't a turn based thing, its real time action... if I'm not specifically commanding them to do stuff, I would hope they'd know they can turn on Carnage without me telling them to.
Lastly, they need to hire a different composer for the music. There's very little of mention, and most of it is dull and uninspired.
Other than that, everything else has been wonderful. The conversation system is perfection and is probably, combined with the story, my favorite part of the game. The graphics are great even with the texture pop-in, and I'm already thinking on how I'll setup my second play through.