I’ve been on the hunt for a lightweight, rain-proof running jacket for spring and summer and ordered the Brooks LSD Lite Jacket II from Amazon, though the actual seller was Night-Gear. There are newer versions out (the LSD III and LSD IV) 
and lots of colors, and the price varies depending on version and color. I really like the Brite Green/Black color I got, and the price can’t be beat.
Fit- and feature-wise, this jacket is awesome and is just what I was looking for.
I ordered a medium and found it very roomy and comfortable. While I don’t anticipate wearing many layers under it, I think a tight-fitting jacket might stick to sweaty skin in the rain. If you are in between sizes, I’d consider sizing up. Here you can see how roomy it is. The length comes to mid-hip and is ideal for me. It’s a little hard to see, but there are reflective strips at the bottom of both arms as well as the bottom of the jacket.
There is cinching at the back, which makes the back view flattering.
You can also see the venting in the back.
The bottom of the jacket has two different drawstrings, one on the right and one on the left, so that you can adjust the fit of the bottom so that it’s more sung in very rainy or windy conditions. You can also see two reflective strips at the bottom.
The hood is form fitting to your head, which will be great in the rain.
The hood also has a drawstring, so you can cinch it as tight as you want. I think this is a great feature and will really help to keep the hood up.
There is a back pocket that the jacket can stow into. You can also see two reflective strips at the bottom of the back of the jacket.
This video shows some jacket features, including how to stow the jacket into the pocket.
I have to mention the tags too. I hate when products come with no information. Both Lululemon and Athleta are skimpy on product info and usually only use tags with obscure icons as warnings or instructions. The tag on this jacket was in booklet form and gave lots of good information.
Bottom line is that I think this may be a perfect running jacket. I love the comfortable fit with drawstrings for making the bottom and hood more snug snug-fitting hood to prevent rain from getting inside the jacket venting so that I don’t overheat in warm temps reflective details and bright color to be seen on gloomy and low-light runs light weight at just 4.3 ounces.
I’m actually looking forward to a rainy day so I can test out the performance, but this jacket gets very high reviews for standing up to the rain. Also, it’s wind-proof, so I’ll be able to wear it on chilly, windy days over a light layer.