I've used both Jetcoat and Spectrum and I am happier with the results from Spectrum for a couple of reasons: 1) cheaper 2) the coating seems thinner and more like paint----the word "Ciocc" embossed on the seat-stays was basically lost when I had the frame re-coated by Jetcoat whereas it was clearly visible the first time I'd had it done by Spectrum.
The turnaround was a few days for both companies. The colours are pretty much limitless for both companies. Spectrum doesn't sandblast it for you like Jetcoat does. I paid $75 for Jetcoat to blast and coat my Ciocc black and paid Spectrum $30 to coat my Colnago conversion black.
edit: Now that I think about it, I don't think Jetcoat actually sandblasted the Ciocc, I think they just powder-coated on top of the old coating because there really is no way that embossing would have been filled if it had been stipped, it is just too deep. I noticed on the fork that the old rust bubbles seemed to still be underneath the coating, so I really think they just powder-coated the frame/fork without blasting it. Damn.
Map to Spectrum