There have been other members here that have reviewed their experiences with aftermarket harnesses. Mostly positive from what I recall, there are some differences from the stock harness in some cases, probably due to the attempt at covering more than one model in some cases. At least the harness is easier to get to than the cam chain tensioner, and it's not likely to destroy your engine!
I would say that an aftermarket harness would be a worthwhile investment to replace a stock harness that has hacked up and/or has severely corroded connectors. Hopefully some of those with first hand experience will chime in.