If you are trying to get across the state in a hurry 80 is the route. Interstate highway with relatively frequent services.
If you want the scenic and interesting drive, with towns along the route that look like they have not changed since the 19th century frontier mining heyday then 50. If you want to stop for the night there is an almost infinite amount of boondocking.
There is a lot of empty between services along 50. So fill up in Ely or Fallon. There also is a lot of empty between Ely and I-15 in Utah. Plenty of traffic, so if you get stranded someone will come along shortly.
We prefer 50. We see something we haven't noticed previously every trip, and occasionally foray off along some unmarked dirt road in one the numerous mountain ranges crossed.