I don't know anyone who "rents" games from PSN+
Most of their games are discounted or at the playa prices so I do see why someone would rent them.
Especially if they disappear...
I only had PSN+ for a few months and I still got all the games I downloaded when I had it
I had gamefly a few times and its cool for a couple of months but then when a new games comes I normally have to wait quite a long time to be able to get them. It gets kind of annoying afterwhile and I end up getting a game I don't even feel like playing.