TT and Sky both get good reviews (in build quality, and customer support). I owned a used TT YJ kit, and I was VERY impressed with the build quality. I called TT with some questions about how to install it. I told them it was a used kit that I didn't buy from them, and they still helped me out anyway - I thought that went a long way to show what kind of customer care they have.
RR tends to get complaints (both in build quality and customer support). I have very little experience with RR, but I've e-mailed RR a couple times with questions, and got really bad replies (made me wonder if they read my question) if I got a reply at all.
While I'm at it... I've purchased a lot of things from Rick at
http://www.hawksuzukiparts.com/ and been VERY happy with their prices / customer service / parts quality. They have a TUN of stuff that isn't listed on their web site (they're a dismantler too, but you'd never know it from their site).