I've been watching this for about the last year, and really enjoyed it. The pace seemed to slow down during the middle of Season 4, but then the drama increased in Season 5; I'd say my favourite episode of all was Season 5 Episode 6, aka the shower scene episode.
As for the finale...
[Spoiler (click to open)] I expected Romero to die, but didn't expect him to die so soon into the episode.
It was good to see Norma appearing a lot, if only in hallucinations/dreams - seeing Norman driving around, thinking he's in a completely different time, and talking to her, was really disturbing and messed up.
So, at the end, I'd always predicted that Dylan would die, and it would just end with Norman running the motel and acting like everything was normal.
I definitely wasn't expecting him to kill Norman; that was a bit of a shock, so it would seem that the TV series did not follow the canon of the films at all.
I suppose the grave with Norma's name on one side, and blank on the other, in the previous episode should have been a clue. Overall, a decent ending to a great show.