I plan on buying a 50D this month ... I do have a 30D, 20D & 300D
my reasons, and I want to see the comparison, is the higher ISO performance
In July I began shooting agility inside, I walked away wanting higher ISO capability and still have a good burst ratio, so I began saving for a 1DIII, then the 50D was announced, and I want to see how it does before I put down the $$
I've been shooting running/jumping dogs on the 30D/20D at ISO 3200, 1/160th f/2.8
would love to get a faster shutter speed, and maybe be at f/5.6-8.0
that's my reason for the 50D
I have a 30D and a 40D. If anything, I'd sell the 30D in favor of another 40D. I'm very pleased with the performance of the 40D, and see absolutely no reason to upgrade "just because...."
Im ditching my old 1d's, and picking up 2 50ds. Granted, the 50d is slower than the 1d and not as well built, but the high ISO is a godsend for photojournalists on a budget.