Bleddyn, I haven't noticed any picture problems. But, I should note that I have a huge inferiority problem whenever I discuss PQ & SQ of hardware/software.
My display is a 26" Samsung HD CRT, I've got an older entry-level Sony HT receiver (STR DE-445), and my speakers are Polk R30s, CSi25, and R15s. Until I won the Blu-ray in an HTF contest, I was using a Toshiba 1600 as my player.
So whenever, I recommend hardware/software, I feel compelled to add my equipment situation as a caveat. (I need to finish my review of the DMP-BD10 and I'm hoping it will provide useful information on adding an HD player to a low-end system.)
But, back to your question, I picked the box up because the receiver only has one set of component inputs and I was hard pressed to route my DVD player AND my HD DVR (I have since added a DVD-recorder to the mix!). I noticed no signal degradation at all when I added the box between my sources and receiver.
I guess I would recommend that you could always buy one to try and, if unhappy, return it.