I took this twice in as many months and happen to really like it. I get home in time to have semi-decent sleep and have all of Sunday to relax.
Both times I took this, they were looking for VDB's.
Upgrades have never been a problem - no sweating it out in my experience.
The airport is dead on Saturday night, which makes checking in and security that much more tolerable.
It prices out cheaper than taking one of the Sunday flights, which can be pricey at times depending upon what's happening in LAS.