My Painless setup was anything but. Three different circuits were mis-wired from the factory... Since they believed the problem had to be with what I did they were no help troubleshooting the system.
Well, almost no help. They did send me an additional wiring diagram so I could see how it was
supposed to be wired from the factory. Once I had that, I rewired two switches and a couple feeds in the fuse/relay block which had been flipped at the factory.
If their stuff had been wired properly it would have been painless... It's hard to screw up when the wires have writing on them telling you exactly where they go. Well except for the accessories circuit their description of what to do with the accessory wiring was very vague.
For what you pay for their stuff it should be Painless.