They went out in true Psych style - insane, out-of-control and hilarious.
Getting the real "Bud" was a nice touch. I was expecting them to show the SFPD's consultant was either a returning character or a cameoing guest star (a la Val Kilmer, who seems to have slimmed down a ton).
It was a very nice touch to see Lassie break the DVD before anything was said. That way, Shawn came clean, but it wasn't revealed. Best of both worlds. Lassie got the position he wanted and deserved, his scary Senior Detective ensures that the citizens of Santa Barbara will be safe without Shawn, and Buzz gets to move up.
Juliet and Shawn get to be together again, but most importantly, the pairing of Shawn and Gus continues, since they basically complete each other (sorry, I realize people want the romantic relationship between Juliet and Shawn to work out, but Psych is an 8-season long bromance/buddy comedy).
Glad we finally got to see the hilarious scene of Gus running away screaming that featured in the opening titles. I can't imagine how many times he had to do that - it's a fairly long, continuous take, and he's running through a forest in a suit and dress shoes.
I was very happy and satisfied with the outcome. As they said on the After Pshow, the world of Psych continues - we just won't see it each week.