Whoever you deal with, make sure they're a straight shooter. (Frank from Clubman is, and I have no information about Skin and Bones.) I got mine from CNW, and was glad I did, cause it turned out I had a bad regulator (not CNW's fault), which Sir Matt was able to diagnose over the phone. He had a new one posted to me as soon as he hung up; solved the problem.
Sparx is good stuff, this is an unlikely problem. I'm just pointing out that the lowest price isn't everything (it is certainly a factor, that I agree!).
Good luck. BTW, I love the Sparx set up. Plenty of power, battery always fully charged when I come back from a run (attested to by the Battery Tender turning to "green" quickly).