Had the same dilemma before. I had my XT with the 24-70L and 580 EXII. I shoot a lot of portraits before, usually around 200 shots on that day. I don't have the grip on it. At the end of the day, my hand felt sore and so are my muscles on my right hand. Heck, I can't even shoot very well in portrait mode the next day! Then I've upgraded to a 50D. I started without the grip but then again, muscle pains (not to mention the 50D is heavier than the XT). Now I got a grip on my 50D and it works wonders. A bit side heavy if you tend to put the flash on the hot shoe. Sure, it's bulky and heavier, but atleast it works for me most of the time. I wish it also had the AF ON button for live view purposes.