Season five is my favorite season thus far. The various character plots advance nicely and a variety of twists and turns keeps it interesting.
There were fewer scenes that will make you grimace with embarrassment, but that's my preference. Seasons three and four were definitely heavier on this sort of humour. I'm thinking of the episode with the couples dinner date w/ Jan & Michael in Season 4 that was just a torture to watch, nothing like that in this season.
Michael is a bit more normal, which Office devotees may or may not like, but he's still quirky and insulting.
I've re-watched Season 5 more times already than three and four, there are many, many laugh out loud moments, so I highly recommend it.