Tyler V.wrote a review of Arc'teryx Accelero Jacket - Men's on January 11, 2011
This is my multi-sport "go-to" jacket. I have used it for trail runs in cold/wind/drizzle, mountain biking, road biking, skinning, climbing, and hiking. It has been great for all of these aerobic, high energy output endeavors. It sports a near perfect balance between breathability and wind resistance. Over about 50-55F and it starts getting a little hot (while moving) and I would say it gets a bit breezy in winds over 15-20mph. When the wind picks up or it gets a little chilly, this jacket is right at home underneath another layer, either a puffy or another shell. When too warm, it unzips to dump heat, or disappears in your pack. It is lightweight and dries very quickly. As mentioned in an earlier review, the jacket is slightly longer in the back, this is great under a harness or backpack waistbelt and on a bike as well.
The only drawback I can think of would be the lack of pockets, but I can't imagine adding handwarmer pockets would be an improvement to this jacket.
I also tried the Patagonia Traverse, which is somewhat similar, but I found it to be a bit heavier and breathability wasn't quite as good.
For the fit beta: I am 6'0" (182cm) and 180-185 lbs (~83kg), I have a 41" (104cm) chest, 33" (83cm) waist, and am 48" (123cm) around the outside of my shoulders. At these measurements, I occupy a massively annoying middle ground between medium and large in Arc'teryx and Patagonia gear and I usually wind up bouncing between the two sizes depending on the cut of the specific jacket or shirt. In this piece the medium fits perfect, not too euro-slim and just enough room to comfortably fit a t-shirt and/or a midweight base layer, no more. I tried the large and it was pretty baggy, to the point of being annoying. I don't think the jacket was meant to layer much underneath it, so I stuck with the medium and I've been very happy with it.
Bottom line: This is a perfect "approach"/"action" jacket. It has worked great for me in this role in many sports and many conditions.
Photo is near the summit of Mt. Hood last August.