Not sure about the Ds, but based on the difference between my home C530 LCD and a C5000 LED at the office (both entry 50Hz), I prefer the picture of the LCD (also less reflective).
I'd be hard pressed to spend the extra for a D5000 over D550 if 2011 models are similar.
I agree, I also preferred the 5 series LA over the UA but that's taste preference. Still an amazing deal!