I have the 550 and the 720. Both do the same thing except on is color the other black and white. The 720 169.00 at Costco. The 550 39.00 at Amazon.com. 550 is a better value.
I assume that the 39 is a typo. Anyhow, I'm trying the 550 now. I'm having trouble programming macros (I have a 4x3 tv with anamorphic squeeze via remote with 7 or 8 keystrokes and I'd like to set up two programs, one for watch wide screen dvd and one for full frame dvd and so far I'm not having much success).