I started using these ROMs recently. 7 worked fine but 8 was having the exact same buffering problems described here. I knew it wasn't my network or my NAS and even with 100mbs, there should be plenty of bandwidth for movies twice the size as I'm trying. No mater what I tried, none of my Bluray backups would play without skipping/buffering. I wasted a couple of hours messing with settings, with no luck, and I finally got these rips to play 100%. I tried so many things so I can't be certain that this is what finally did it. But what I think it was finally was messing with the advancedsettings.xml file. Setting
<memorysize>50000000</memorysize>
<buffermode>1</buffermode>
<readfactor>6.0</readfactor>
is what started it working for me. Let me know if this helps your guys' buffering issues. I've only gone through 2 movies but I'm hopeful. I'd rather not run android.