Hmm...
The 3.0 host port is practically useless as a network shared drive since the eGreat can only do 100 Mbps and not gigabit ethernet. If I had a USB 3.0 drive and I needed to transfer files, I would skip the middleman with the slow ethernet port and just connect to the source.
Also, there should be no improvement in PQ or AQ as the bandwidth needed for DTS-MA/Dolby TrueHD and 1080p can be run through USB 2.0 without any problems. Someone please correct me if I'm wrong.
The X5 has more I/O ports, an hd tray, backlit remote and gigabit ethernet for just a fraction more than the eGreat R6S. It can also work well as a good enclosure/NAS due to faster throughput c/o the gigabit eth and USB 3.0 output port.
Assuming firmware and build quality for both are equal (I have no idea as I don't have both), I would say the X5 would be way ahead of the R6S.
A few hours after pasting this comment, it got me thinking real hard and...
I ended up buying 2 X5's the following day.
One is connected to an AVR while the other is connected to a tv and to an HTiB via optical. The one connected to the avr is doing just fine.
It is definitely better than all the other nmt's I've tried. BD-ISO's played flawlessly and the ones with menus worked great, too. Gigabit ethernet is always great to have and the extra USB ports are definitely most welcome.
The one connected to the HTiB seemed really sluggish, it seems to boot much more slowly too. In fact, the browser and Android apps never seem to want to run. I have a feeling it's because of the extra optical connection to the HTiB. It moves much faster when I put the HDMI setting to LPCM and the SPDIF setting to LPCM as well.
When I put the SPDIF setting to RAW (HDMI set to LPCM to save bandwidth) and the surround setting to 5.1, the player stalls and you would have to stop the video file from playing. When I put the SPDIF setting to LPCM, it works fine but can obviously only output in stereo. I am now trying different combinations/solutions to see how to output DTS via optical to the LG HTiB. I will also try different firmwares to see if there is one which actually already solves this.
Any insight from the other users would definitely be appreciated as well.