I don't pretend to know much about high end instruments, and I'm mostly an acoustic player but this RB600CS has given me more enjoyment than any electric guitar I've owned. The only issue I had with mine was a badly manufactured bridge saddle on the 2nd string. It was slightly wobbly and if I did a string bend it would move.
I fixed it myself by filing down the bottom side slightly until the wobble was gone and redid the intonation. After that, this guitar has been absolutely inspirational for my playing.
It features a volume for each pick up and you can blend them in the middle position of the 3-way switch. The tones are great through my Fender Champion 40 amp (In my home studio) on Blackface or British amp models, and there isn't a single blemish on that finish worth mentioning. I did a DIY mod to the pick guard because on real Rickenbackers the pick guard is elevated off the main white tear drop. Other than those two things I haven't touched a thing and I don't plan on it either.
Buy it. You'll like it A LOT.
* 6 Month Update*
Figured after 6 months with this beauty I'd give some long term impressions. 1.) I have not replaced anything electronic on the guitar. It just doesn't need anything else other than what Thomann gives you out of the box. 2.) You have to know what tone you want if you buy this guitar. If you want to sound like Tom Petty or the Beatles, you'll find those sounds. If you want to sound like Metallica, buy a metal guitar, this isn't designed to do that stuff. It's a classic rock/jazz/blues guitar, not a metal machine. 3.) I've read other reviews that try to explain what this guitar is. It's a tribute to the entire line of Rickenbacker. The body is actually more inspired by their bass guitars than the 660 small body like Tom Petty has on the cover of Damn the Torpedoes. And it works. The thing is GORGEOUS to just have a look at while it sits in one of my guitar stands.
4.) In the six months I've owned this guitar I haven't gone a full 7 days without being forced to pick it up and at least strum a Petty tune or Beatles tune just to get a few notes out of it... It's that much fun to play.