Both superb bikes, although you honest to goodness cant go wrong with either I think the 26FS will give you just a little bit more room to explore and take risks in the technical downs than a HT.
I have both these class of bikes (different brand) and it's hard to choose one over the other. Both climb like billy goats with the slight edge maybe going to the 29er HT, the 29er will make you grin with what you will find you can roll over that you would otherwise had expended some extra energy and skill on a 26" HT. For me both bikes allow me to better manage my energy expenditure give me cush to manage hits and impacts that I would otherwise have noted on a 26" HT. You'd be happy with either interchangeably in most scenarios but I'll give the edge to the 29er when you have to go up but the margin of safety, forgiveness and comfort when going down steep, rocky and rooty declines to the FS.. The truth about a HT still remains...it is hard. Cushy tires are not to be under-appreciated, they mean everything with regard the enjoyment, comfort and control you have on your ride and IMO the biggest factor in making a good bike great but there is more forgiveness on a full squish.
I'll vote RZ 120 if the coin is okay with you. Truthfully you cant go wrong with either, gawds honest truth, they complement each other so well that their envelopes overlap up to the 90-95% mark. 29er for UP and DOWN, 26 FS for bumpy, chunky, "OH $#!t" downs. Neither bike for hucking, big drops or general clumsy boulder bashing.