The Amp range mentioned are great and as mentioned, used by specialised under license I believe. They are also possibly the lightest full sus bikes you can get. I have a litespeed ti version of the b3 in a box waiting (for a good few years now) to be built as well as an amp b5 (again still waiting to be built). The b5 was the last of the amp designs so should in theory be the better one. If memory serves, the b4 and b5 are very similar, but with the b5 I think you get a standard style shock as opposed to the proprietary fit units, so you can fit a nice modern air shock and make the bike even lighter, and benefit from the evolution of the rear shock too.
I must admit that I do love my rts, but I'm no racer so don't really notice the flaws pointed out. My sts hasn't been ridden since I upgraded it to bearings rather than bushes, and an air shock at the rear, but it rode well with the stock rear end aside from the slight creaking.
I must admit that I do love my rts, but I'm no racer so don't really notice the flaws pointed out. My sts hasn't been ridden since I upgraded it to bearings rather than bushes, and an air shock at the rear, but it rode well with the stock rear end aside from the slight creaking.