You wouldn't be able to watch Amazon HD movie streams through playon (HD TV episodes might be possible, since they work through their PC player).
The new Panasonic BD players had the best Amazon player that I'd tried and the same Netflix UI as on the PS3 (they have a suite of streaming media apps called "Viera Cast" which includes Netflix, VUDU, Amazon, CinemaNow, YouTube, Pandora, Video Skype and a few other things), so I bought the DMP-BDT110. I cannot, however, recommend its DLNA client function. It does have one, but it's severely limited--the files I could play from the TVersity server running on my PC played beautifully, but I couldn't PAUSE, FF or REW.
They have pushed a few firmware updates since the product launched a couple of months back, so they are improving it. Perhaps its shortcomings will disappear over time. I don't really care about anything except Amazon, since I own a PS3, Xbox 360, TiVo Series3 and this PC, all of which are connected to my AVR and this 1080p LCD panel, so I can play everyting except streaming Amazon in other ways.