I’d go with a full suspension. It looks like Yeti is discontinuing the ASR, or at least they aren’t listing it on their website any longer. Competitive Cyclist is closing out the “Beti” version of the ASR, which just means it has some purpley/pink writing on it. Good deal if you can ride a large frame and don’t mind the color.
The Tallboy is much more of a short travel trail bike than a true race bike. It’d be a good all-around bike, but if XC racing is your thing, I’d steer you away from it. XC racing isn’t nearly as popular as it used to be, which is why smaller to mid-sized manufacturers (Santa Cruz, Yeti) are focusing their efforts on trail bikes.
The Epic is a good bike, definitely a straight up race bike though. Another one to consider is the Rocky Mountain Element, I rode the shit out of one this summer, and I really, really liked it. Basically, it splits the difference between the Epic and the Tallboy. More trail worthy than the Epic, but not as slacked out as the Tallboy.
Other options to consider: Specialized Camber, Giant Anthem, Salsa Spearfish, Pivot Mach 429, Kona Hei Hei
Here’s my review of the Element:
Pisgah Tested, Racer Approved: 2017 Rocky Mountain Element 970 RSL Review