ThzBT rips might have had some issues early on but their rips have been fine lately. I just went and checked a few of their rips (KTDS-880 and HND-319 specifically) and seemed to play and seek smoothly.
Here are render stats from MPC-HC, maybe someone can make some sense of it:
View attachment 792090 View attachment 792091
From what I know as long as that graph on the bottom is flat then playback is smooth.
This is what a bad one looks like (MXD-036):
View attachment 792102
This video is completely unwatchable. It's practically a slideshow.