I rated this episode a 7 though my actual enjoyment of it would be a 6. It's a tonal shift from the normal series and as such, watching right after finishing the series, felt a little jarring to me. It's much more silly, laid back and "filler-ish" This is why my enjoyment was only a 6. HOWEVER. AS a Filler/side episode I think it actually did it's job at that specific role quite well. They are often a different tone and more laid back and "fluff" as it were. I think for the genre of "side-episode" where you're not going to thedramatic tension route, or the sterotypical beach/swims-suit episode, it was done well enough. A touch of the absurd, a reason why the main character wasn't present etc.

It's not a "have to watch" or even probably a "should watch" episode. It's a "watch if you feel like it" episode, and for that particular purpose is fine.