I love ME2 - on my 3rd play through and it is alot of fun the play
The only problem I have with the game is that it feels like the 'real' story (ie, collectors etc) is about 2/3 missions long.
You start off and say "Oooh! Collectors bad, lets stop them! But first I need to assemble a kick ass team!" - ok I can live with that because the 'aquire' quests are good in themselves.
Once you've got your team, in order to actually finish the game without them all getting wasted you need to do a loyality quest as well. You always get a dialog option that says "If we have time", but there is NO time limit before the collectors do anything really bad - so you've got more than enough time to keep everyone happy.
If you do all of the team member quests & loyalty quests it feels like you start off saying "Lets get this damn alien abductors" but each guy you meet says "but can you take me here first please" and the game becomes more and more about pleasing these guys than doing any collector ass kicking at all.