I just got this jacket and I am very happy with the purchase so far. I am 5' 9" and about 165lbs. I purchased the XL and it's a good form fitting jacket. I can wear a couple thin layers underneath and it doesn't feel too snug. I also inserted chest pads and I can still zip it comfortably. Not a lot of spare room, but I wouldn't want it loose.
I have a 22 mile commute to work in Northeast Texas. On cold weather (cold for me means below 45º) this jacket performs superbly. I don't feel any wind at all on my chest at high speeds (70-80mph). I'm sure I can use it in substantially colder weather and it would still be toasty warm. The thermal zip-in jacket is very stylish, which was a big selling point for me.
The shoulder and elbow protection isn't obtrusive and is CE rated. The back foam pad is really not protection at all. If you are concerned about that then you definitely want to upgrade.
The sleeves are snug not tight, so if you have giant forearms then it might be kind of uncomfortable for you. There are no adjustments so you can't increase the volume.
It would be nice if they designed the inner liner to attach to the sleeves at the cuff. When you take it off you have to reach inside and grab the inner so it doesn't bunch.
I chose this jacket because of the Taichi brand (I also own the Vox mesh jacket) and because of the nice styling. You can wear this jacket anywhere and not feel like you are screaming motorcyclist, which in most cases is a nice thing.