I recently had to buy a CF for my Rebel XT, and, after considering the transcend, decided to go with the 4GB Ultra II for about $10 more. It may be a little slower, but it still pretty fast for the camera, and those cards are incredibly reliable - I have a 1GB card a 2x2GB cards that have seen quite heavy use in very cold (Toronto), humid (Costa Rica) and hot (Jordan desert) weather, and I've never had a problem. I think reliability is #1 for me, as I would hate myself if I ever lost a great picture for saving $10.
That been said, I would guess Trascend cards are also pretty reliable. They have excellent reviews, but I haven't had any experience with them. I have more faith in them than in Kingston. A Kingston 2GB SD card I got for almost nothing from Amazon (promo when buying a camera) a couple of years ago became unreliable after a year or so - sometimes my card reader would have trouble recognizing it, and would appear as unformatted.