Haven't used one, but I understand that it's a generic kit that needs alot of head scratching to work. I'm starting to rewire mine, just using an assortment of color wire from radio shack and hoping for the best.
Don't know about Painless, but the knockoff brand from JTOutfitters, well lets just say I wouldn't be surprised if I went gray from it (and I'm only 19). The big difference that I would say is definetly worth the money is that it looks like from the pics of the painless kit that it includes the connectors you will need.
Plus, a generic kit isn't all that bad if you want to modify your setup by adding lights or really anything, well there are wires supplyed in the harness that a stock 40 won't need, but they're already wired into the fuse block.
the painless is good quality harness, it does require adaptation as it is a general harness. however, Ive learned a lot installing it and would probably do it again. only thing i would do differently is throw the butt connectors that come with it away and solder everything from the start
I put a painless kit in a cruiser once. Was fairly easy and took a day to do, but I know automotive circuits fairly well, and this was a Chevy V8 and chevy column. The kits are labled well, but usually require attaching to a connector pigtail, unless they have changed them in 10 years.
The hard part will be wiring to the dash, turn signal, and switchs as they will only be power leads to those circuits. You will have to use or make the rest of the circuit. The engine and lighting circuits are good.
Like thorvald mentioned it is a good learning experience, and you will understand the wiring of your rig when done. But if there are only small things to correct, just fix your harness...go for the painless if its far gone and needs most things replaced.
And it was a pain in the a$$. I had a totally hosed wiring harness, so I needed a complete rewire, so it probably was the right thing to do. However, I wouldn't do a painless kit unless everything is gone.
If you do replace, let me know. I had to add rectifiers and some other things to make it work right.
Also, technical a$$istance from painless was useless, up until the last guy who figured out that I needed to go out and buy extra parts from Radio Shack.
IMO, you will understand the wiring better and be $$$ ahead in the long run if you rework your factory wiring. I pulled mine a few years ago and laid it across the driveway, patterned like it would be in the rig. A few hours of cutting and I had trimmed out a few hundred feet of unused wire and understood the harness. (I removed quite a bit of things from the truck, like heaters and junk) I use heat-shrink crimp connectors on mine with no problems...personal preference, IMO.