Jim: Not as comfy as vented gear obviously, but the Klim jacket/pants have both front and rear vents that give you pretty good flow-thru ventiliation when moving. Jacket is well-vented, but I did resort to the use of a cooling towel around my neck when riding across TX. Even at 90+ MPH, it was like riding into a blast furnace. When touring, I carry a set of thermal liners for top/bottom and typically use 'em if I'm gonna be putting in many hours in the saddle at temps under 45-50. As Tim noted, the jacket is not quite as well lined as some other high end gear, but that also makes it more tolerable in hot conditions.
Prior to picking up the Klim suit, I had an Aerostich Roadcrafter onesie that was both hotter and less comfortable. Wore it for several years but never came to love it the way some folks talk about it being the gold standard of touring gear. Whenever I stopped, I always wanted out of the 'Stich ASAP, whereas I wore the Klim pants full-time on my trips.