I got the Sammy LA40B550 and BDP1600 deal from Makro a few weeks back. I was also torn between the Sammy and Sony displays and my decision came down to looks, that's how close these panels are in performance. The Sony is a *little* better at upscaling SD images, but the Sammy just beats it in looks. I couldn't see a difference in HD signals between the two, although I did not spend hours doing comparisons.
I'm running these through my Yamaha RXV861 amp in HDMI and I've honestly had no compatibility or switching issues.