Prepare for a 'wave' of opinion.
I'm 5ft 11", but long in the torso for my height and ride a medium. I was told that I could also ride a large, but there's no way a large would have been right for me as it would simply have been too long in the top tube. Even on the medium I run a 50mm stem and it's about right; the TT could even have been .25" shorter.
I think most people however would agree you need a large and I wouldn't neccessarily disagree with that, but there might be a case for a medium; it would just depend on your style of riding and what you've been riding before. Certainly on a large you'd be wanting to run a max 70mm stem IMO.
As for whether they are the 'be all and end all' I would say no, definitely not. The market for good quality, long travel hardtails is just too rich, colourful and well developed for one bike to claim dominance.
Having said that, they are truly brilliant and handle like an absolute dream. On moderate terrain they carry speed almost as well as a mid travel full suss bike; they're forgiving and have a lovely temperament. They are quite flexy though, certainly for larger, more powerful riders (I'm 110kg) but that doesn't detract too much from their sweetness and finess.
I was going to sell mine having only had a few months, but I've since realised that it is a fabulous machine for the money and while you could spend twice or three times the amount on something exotic, I can't see it adding much value to the experience.