First of all, the stats. In a Men's Small, it weighs about 180g, which puts it on par with something like the Salomon Agile Jacket, or The North Face Torpedo. Not super light weight, but still pretty darn light. It has 2 zipped side pockets, several reflective strips, and that's about it for features. But, the details are where this jacket shines. All the seams are taped, the zipper seals to keep out rain & wind, there's a super soft stretchy cuff on the wrist, and decent vent on the upper back.
I wanted to test this out in a lot of conditions before doing this review, and this jacket has stood up really well. On the nasty end of the spectrum, I had a couple of runs in absolutely miserable weather- a degree or 2 below freezing, with heavy, wet sleet coming down. I wouldn't expect any running jacket to keep me dry in those conditions, but this did surprisingly well. Minimal moisture got through, and the vent on the back kept me from overheating.
Beside the nasty weather, I've been wearing this in a lot of other conditions. I had always tended to try to ditch my old jacket as soon as it got much above freezing, and just go with a long sleeve shirt with a tech t shirt over top, but most mornings I found myself reaching for this jacket instead of the long sleeve/ t shirt combo. When it was just a bit above freezing, I found that having a t shirt under this was perfect.
All in all, I'm super impressed with this jacket, and from what I've seen of the other MPG Sport gear I've been wearing (I'll be posting a review of the Muscle Shorts soon- http://ca.webstore.mpgsport.com/p-889-muscle.aspx) they're a legit provider of high quality running gear. I'd have no qualms at all about using their gear for a super long run or ultra marathon.