Rain Cover for T2i/550D?
 

Because the T2i/550D isn't weather sealed like its bigger brothers, I was thinking of getting a rain cover for it for the odd occasion if I get stuck in the rain/sleet/snow and need to keep shooting.

Looking at the Kata E-702 cover a few issues come to mind. Control over all the buttons is a good thing, but does this cover offer enough enough control over the lens, especially on a continuous 12 minute shot? Also, concerns about the dreaded overheating arise, but I would assume that depends on the particular shooting situation.

Does anyone have experience with rain covers and their DSLR's? Is it worth getting a rain cover or would a garbage bag or shower cap be just as effective? The only problem with a garbage bag is that I'd like to look professional (even though I'm using an entry level DSLR).

Any comments or alternatives would be greatly appreciated. Thanks guys!