I did a good amount of research on harnesses, including the Tree Spider. I like the idea of the LiveWire unit, but haven't opted to buy one yet. I conciously avoided the TS Harness, mainly due to how it adjusts and fits. I looked at Muddy, and ruled them out. I looked at CDS and ruled them out on weight and bulk: I can be as safe (or safe enough for me) with less weight/bulk up there. After running the gamut, I went with the TSS Extreme Harness (not vest).
I'm currently evaluating the LiveWire from TS, as well as going with a fixed climbing/safety line. My gut tells me the fixed line is the better system.