I've been using my JTK Red & white for a very short time period, but I came across something a little sad.
http://imgur.com/xQzNW9VThis only happens when the set is combined with the mx compatible topre sliders from JTK. In other words mx stems and the keycap set have no issues.
It doesn't seem to be an issue for me while just typing regularly. I only noticed because my finger slipped on the z key while testing some random stuff, so I decided to check if the motion would pop any of the other keys off in the same way.
Other than that everything is pretty good. All the mx compatible sliders feel smooth. I had to modify the left control on my Realforce 87u because as previously mentioned the housing is simply different and won't accept a regular slider, and I also had an issue with my Num Lock casing not being able to receive any of my mx sliders (they were simply too thick), but I just swapped the housing from one of my FC660c so everything is all good there.
I'm not sure if this is an issue with the stabilized sliders or if it's just the keycaps, but my stabilized keycaps have a rather sharp return sound compared to my other topre boards. I'll have to get back to you on those though.
The keycaps feel really great by the way, and I don't mind any small imperfections as I really have to put my nose to the keycaps to find them most of the time. Great set for a great price, and if JTK are able to keep improving I will keep supporting with the little bit that I can.