I actually liked season 3 (after they stopped making stupid pot jokes)
I think season 3 has some really strong episodes, but there's problems you have to get through to really enjoy them..
For starters, they got rid of a lot of the characters and ignored all the dangling plotlines. What happened to Camomile White? I guess she went into her light. I don't know. If it was addressed, I missed it. They got rid of the drug dealer friend which I don't mind as much (he wasn't the strongest character) but he deserved a better send off. It's like Hulu banked on people watching this show for it's potty/drug humor and not for its characters... Which leads me to the next problem...
They really upped the drug humor and the potty humor. Fortunately they find a nice middle ground partway through the season, but those first few episodes were a pain to get through. Too many jokes about how cool smoking weed is and what not. It's just not funny. I don't mind risque humor though, but I can see some of the potty jokes irritating old fans (but let's not kid ourselves and pretend the show was above this sort of thing... the first episode is about Pac getting high and having sex for a ghost...).
Still once things get started I think season 3 has some of the strongest material. It introduces a character who can actually see ghosts. I was more interested in seeing where the Danny Poker plot was going than anything with Camomile White. I think some "bromance" stuff is fitting with the character of Pac and the universe of the show. Kal Penn is a funny guy and an inspired choice to bring to the show. I liked his character better than Rufus, who he seemed to replace. I liked how they kept bumping into that necrophiliac woman. I think the LARP episode is one of the my favorite ones of the entire show.
With that said, I'm glad the show ended. It's never been very great and the good aspects of this season don't change the fact it was a mess.