ME1's gameplay was sub-par, ME2 fixed it, and ME3 more or less perfected it. The RPG elements in ME3 were pretty great, too...except for the Fitness talent tree making you choose between high defenses and high melee damage. That doesn't even make sense!

First one is good only for introduction to the galaxy, reapers, the council, and Spectre's.
Second one is the real gem in the series.
Third one pretty good, mediocre ending (talking about the extended cut).

The big thing is with the whole series, some of the content that is the best, is sadly DLC.
EXAMPLE: Lair of the Shadow Broker.

Yeah second one's a gem if you like spending the entire game getting party members for one boss fight.

Maybe if you read my comment again you'd notice the hyperbole.

I didn't mind it.
I liked all the members of the second game actually.
Kasumi and Thane made for the best dialogue.

Also I did so many of the extra shit in the first and second game, including their missions, which benefit you quite a bit.

Pick it up at ME2. The first one didn't really know what it was trying to be, but in my opinion, the second one nailed it