I’ve only watched the first season of Fate/Kleid Liner Prisma Illya so far, though i’ll probably move onto the second soon enough. It’s interesting seeing the Fate characters in a new setting even if their personalities don’t match their original story counterparts. I may yet write a review, so i’ll leave my thoughts there for the moment.
Starlog is the series’ first OP, and though it sounds fairly generic to begin with I quite enjoy the song overall.
The Geek Clinic 
This opening makes the show look so much more innocent than reality. Some poor unsuspecting Sailor Moon fan has fallen victim I’m sure of it.
I went into the show thinking it was sure to have a whole bunch of fan service, so I was pleasantly surprised by its relative lack (second season seems to be ramping it up, though =/).
I think the combat effects are pretty and the Fate cameos are enjoyable. The series itself? Average.
Yea, great action scenes, and the series itself is a pretty fun spin-off, if you don’t expect much to begin with. There’s also… yuri… but I assume you don’t really care about that
I won’t say it’s a turn-off, but I don’t look for it when i’m after new series. I’ve started the second season now and i’m kind of disappointed that they’re not indulging in more Fate cameos.
Kuro is pretty much an Archer spin-off though, so that’s great, I think.