I, too, have a 717. I heard that the 828 suffers from purple lines along certain edges in photos, as others have mentioned.
I took my CF to CompUSA to try out (as best you can with them tied down) the 828 and Rebel. Sure enough, I two pictures of the same shot and one of them had the purple lines. That turned me off from the 828 right there. I wasn't going to pay $1000 for a "minor" upgrade that actually resulted in worse pictures. And I was looking forward to the better video as well as MS/CF support. I have a 1GB MS and 1GB CF, so that would have worked out nicely.
I also tried the Rebel and several things kept me from taking the plunge. I started out with digital cameras, not SLR film cameras. I like being able to view my shot on the LCD screen that swivels (my old FD91 and the F717 allow the screen to swivel up and down). This allows me to take a picture from down low or up high without crawling on my belly or carrying a step ladder around. That is what I would have to do with the Rebel since you HAVE to you the view finder when taking pictures. I also like the ability to take video shorts with the same device. I still want to purchase a nice camcorder, but video in the digital camera has come in quite handy. The enhanced video capabilities of the 828 was one feature I was looking forward to. It also didn't help that the Rebel corrupted by CF card and I had to reformat it. Going into it, I was really hoping I would like the Rebel. In the end, there were too many disadvantages for my needs to make me part with the $1000.
My brother in law has the Canon D30 with a $1000 lens hanging off the front. I DO like the quality of the pictures, the feel of the camera, the speed of taking pictures, etc. but the same disadvantages still exist. Maybe I just need to own both types and switch between them.
Oh yes. I also own a Minolta DiMage Xt that I carry around in my pocket everywhere I go. With PDA in one pocket, Camera in the other, and the cellphone on the belt, I expect to get testicular cancer any day now. 8O
Seeing some of the other posts, it looks like I'm not alone on most points.