I have used, Ron Francis sub harnesses, Painless, Centech, Rebel, American Autowire & 1 or two I can't recall and have had no problems but with American Autowire, I finished the job and turned on the flashers and the dome light blinked in a 57 Chevy, the factory terminated the dome light lead to the flashers! Since its all factory terminated and finished it was a pain in the butt working upside down under the dash fixing the factories mess up.
One note, I only solder joints, some CEO from the wire companies (can't remember which) said no harness is going to say to solder as they would never sell another harness in a interview, but a proper solder joint is all I do and never had a connection problem. I will continue doing it but as far as harnesses only Centech and Francis's let you terminate to the fuse block if I remember correctly out of the few I have used, all in all Centech was the most I have been impressed with but isn't well known. Best of luck