I like the Sony for a couple of reasons. First of all, I like the movie mode better. You're only limited by the size of the memory card. The Canon will only do timed movie clips no matter what size card you're using. Both camera's take nice pictures from what I hear. I preferred the shape of the Sony. It's a little wider, but I liked the feel of it better. Something about the A70's thick grip that I'm not crazy about. Also, for me, the Sony made more sense because I have a Sony minidv camcorder that also uses the memory stick. If I would've bought a Canon, I would've been using 3 different media's (CF, SM for an Olympus that I have and the media stick for my camcorder).
A plus for the Canon is that you can use adapters for the lens. The Sony doesn't have anything like this. I'm not positive if all the accessories are proprietary or not. I have an older Olympus and I have an adapter ring, but I can use several different brands of accessory lenses on it. I'm not sure if the Canon is this way or not. Anyway.. With the Canon, you can add a wide angle or teleconverter or use filters. With the Sony, you cannot. I bought the Sony for point and shoot and use my Olympus for the lens accessories, so this didn't mean anything to me.
Hope this helps..
Sal