Almost anyone looking at the Mountain Equipment Vega will probably be considering a very comparable Rab Neutrino Endurance. There are slight sizing differences. I am athletic 5'8, 160 pounds with a 40 inch chest. A medium Rab Neutrino (chest size 38-40) feels tight in my armpits even at rest. The Mountain equipment sizing medium (for 40-42) feels much more comfortable in the armpits even with motion. The water resistant Drylite extends into the hood and inner hem on the Vega. HOWEVER, I have a hard time believing this jacket has the 8+ ounces of down that the manufacturer claims. Even when accounting for the smaller baffles, it is 2/3 as lofty as a Neutrino. Both the body and the arms feel anemic of down. I'd guess that my Vega has 6 ounces of down. I've tried on two different specimens, and both are the same. If you want warmth/loft, get the Neutrino. If you want amazing hassle-free zippers and don't mind less warmth, get the Vega.
This review was written in the old system and had content requirements that are different than reviews written today.