Never heard of the others from your list except for Workswell. And Workswell had a good reputation here. But I'm in no way saying the others are bad, they all probably have the same quality frame, probably from the same source. So it is more of a how they would deal with you (i.e. being helpful, polite, and generally good communication and after sales service.
You might also want to check with Peter (Xiamen Carbon Speed) or Deng-Fu if they have a similar frame. These 2 have very good reputations here in ChinerTown.
As for the custom painting, it's pretty much you submit a design (either copied from other bikes or from your own vreative mind) and they follow it and bills you accordingly. I believe they will give you a template for it. Painting is also limited, I mean no elaborate or complicated art. You might want to check out other sections here, some folks had their frames painted so you see for yourself.
