Unfortunately, you don't get thumbnails with recordings of every show -- at least I don't. Does anyone see thumbnails when FF'ing a new recording of The Walking Dead? I haven't yet.
One great thing about YouTube TV that PS Vue never got right is adding 1 minute and 6 seconds to each recording to cover when one show bleeds into the next or starts a bit early. I've noticed every YTTV recording starts few seconds before the actual show starts. That must be the six seconds. Then one minute must be on the back end.
I heard last night there were widespread issues on DirecTV Now and PS Vue during the Oscars. I had absolutely zero problems watching on YTTV. I took a chance watching it streaming rather than OTA, because I wanted to be able to pause for extended periods and then fast-forward through commercials, long acceptance speeches, and other boring bits. YTTV did not disappoint even streaming on multiple TVs simultaneously.
EDIT: Here's something else cool. I just looked at my recording of the Oscars and the time listed for it is 3 hours and 52 minutes, even though it was originally scheduled to run for 3 hours in the guide. I don't think PS Vue ever automatically added time to shows that went past the scheduled time slot.