Since I spend a LOT of time sitting in a treestand in the fall, last year I decided to finally replace my old harness that I've been using for about 8 years. I looked at a lot of them and decided to go with the Gorilla G30.
It's heavy in the hand and is probably overkill, but if fits great, is easy to put on in the dark and you don't notice the weight sitting in the stand. I don't ever want to "test" a harness and I feel pretty confident that this one is built to really work....and hopefully never needed.
I bought mountain climbing ropes years ago and use them to make my tie-off ropes for my stand sites. They are designed to withstand the stress of a falling human. I use smaller diameter mountain climbing ropes to make the prussic hitches. I also make them up and give them to other hunters.
Be safe out there this season and never get in a tree without a harness.