I got one too! I'm not a big guy at all (5'9, 165 lbs) and I ended up getting a Large. It felt a little tight at first, but its nice and broken in now...and it actually feels a bit loose. But it got a lot more comfortable since I got it! :D And surprisingly, its not that hot, especially at speed.
I still prefer the A* TZ-1 jacket I tried on the other day, fit me perfectly! But it was like twice the price.