While I have read comments on the ability of each bluray player to stream video files via dnla or play over USB, I have not seen any comments on the navigation ability with those files. I was finishing the second half of a movie (mkv file) over usb the other week, and found myself straining at having to fast forward through half the movie on my Panasonic 220. So I endeavored to experiment with the Sony 590, Samsung 5900 and LG 620 to see which offered better navigation options to skip around in a file over usb or streaming.
What I found was the Panasonic and Sony are limited to FF/RW with in file. The LG added the feature to skip time to specified point you input (hours, minutes, seconds). This is comparable navigation to the WD Live which I have demoed but not used extensively. The Samsung included all these options so far (FF/.RW/jump to certain time) but also could skip ahead or back about 20s using the arrow keys. That seemed nice for jumping back to catch something you missed.
Since most of this was figured out by skimming manuals and mashing buttons, I am interested to see if others have found ways to navigate within a file on any of the major brands. Please note that I have only tried out the ones mentioned above.