I have the Rab Drillium and I too, am convinced of the worth of eVent. I tend to perspire easily and I have found Gore-Tex, Paclite, etc not much good at keeping me dry on the inside in foul weather. After perspiring too heavily in my Marmot Precip while hiking this fall in a rain/snowstorm in 35 degree temps with a wind blowing, I decided to try the Rab. At about 12oz for size L, it is equal to my Precip in weight and is fully-featured. I wore the Rab while snowshoeing this winter during a snowstorm with temperatures in the low 30s. Even though I was breaking trail in heavy snow with a 20lb pack and had the hood up and the parka zipped completely, I was completely dry from both perspiration and precipitation. I wore the parka for approximately 5 hours without taking it off, and this period covered both snow and rain. I have never found a product that could keep me dry like that! The fit is slim, similar to that of Patagonia's slim fit products, but I can still fit my Montbell down sweater under it. Rab products seem to feature a wire brim in the hood so they need to be stuffed carefully to avoid having to reshape the brim after unpacking. I tend to store clothing loose in my pack so this is not an issue for me.
As for Montane and Integral Designs, I believe their products too are of the highest standards. Everything I own from ID is made in Canada rather than China, as is the case with some products, at least, from Rab & Montane. As a side note, I have a windshirt from Rab in Pertex Quantum and a similar product from Montane in Pertex Microlight. The Montane is a better fit and much more breathable.