I have plenty of chances to test rain gear, living in Florida. Thunderstorms roll through every summer afternoon at 4PM, and if I didn't want to ride home in the rain I'd never be able to commute. My route is long, so keeping cool(or at least not smothering) is difficult. I started with a Performance rain jacket(not the Century, but a cheaper one). It kept the rain off but didn't breathe at all. I bought a J&G rain cape, but I think rain capes work much better on bikes without drop bars. The rain gathered in a pool between my forearms, which pressed the cape to my forearms, making me hot. Plus, in windy conditions, the cape becomes a bit of a sail.

My ultimate solution in summer rain is to wear a helmet cover, Rainlegs(waterproof chaps), and waterproof booties. I don't mind the jersey getting wet, but I can't abide wet feet. I hear the SPD sandal is the best footwear for riding in the rain, but I'm not fully sold on the SPD sandal yet.