Have fun playing ME1. 2 is where it really gets good.
The first is a bit clunky.
I strongly (yet respectfully) disagree. ME1 is a very well-rounded (albeit somewhat limited and repetitive at some points) RPG with FPS elements, with a rich lore, ample room for character development and a mostly airtight plot.
ME2, on the other hand, drags ME1's plot into a dark alley and does very bad thing to it from behind for a sorry excuse to a sequel. The game kicks off by forcing
a rather crucial choice on you (one my ME1 character would never have taken), and then gives you several individual, mostly isolated missions that you can complete in whichever order you choose, all while being sure that what little plot there is will just wait for you to be ready no matter what. Also, forget RPG-ing, this is now a full-on FPS with only the slightest hints of RPG thrown in for good measure, and some walking around between shootouts. That's not to mention pointless gating of content behind a DLC paywall, and some of that DLC outright contradicting the main game's plot and lore. Or stupid collectibles, like your ship is suddenly Second Life or something.
From where I stand, ME2 was a trainwreck. Then again, to each his own.
Wouldn't know about 3 as I haven't played it yet. :P