The Slayer seems pretty decent but it is an all-mountain and might be a bit heavy. It would definitely be able to take a hit with the 160 mm fork. The other bikes you are considering are xc bikes and xc race bikes and this one is not. You would be better off I think and passing on this one and go with a lighter bike and then if you think you need a 6 inch travel bike move up to a bigger bike. The Slayer is on the small side so that might be a problem unless you are around 505. It can be a little bit of a trap to shop by price looking for the "dream bike" If you are young and strong and looking at taking some drops and doing some agressive riding and you are on the shorter side the Slayer might work.
I think a safer bet would be to go with a Giant, Trek, or Specialized XC rig. Here is an example of a bike that I think would make a real decent ride and you wouldnt be kicking yourself because its "too heavy" when you are slogging up a long hill. I think if the price was $200 less it would be very attractive. Its a stumpjumper. The Trance would be a nice alternative to the Stumpjumper and maybe more bike for the money.
http://denver.craigslist.org/bik/1819011864.html
I think a safer bet would be to go with a Giant, Trek, or Specialized XC rig. Here is an example of a bike that I think would make a real decent ride and you wouldnt be kicking yourself because its "too heavy" when you are slogging up a long hill. I think if the price was $200 less it would be very attractive. Its a stumpjumper. The Trance would be a nice alternative to the Stumpjumper and maybe more bike for the money.
http://denver.craigslist.org/bik/1819011864.html