The x bolt replaced the A-bolt which was one of the youngest factory actions on the market. The A-bolt in my mind had and has some big plus's to it. One of which is 3 locking lugs. It adds more interface with the action and spreads the pressure better in my eyes than a 2 lug (Remington, Savage, Winchester) system.
Browning's are fine rifles and demand a lot of money. The X-bolt is a new version of the A-bolt. It should be a good shooting rifle.
There are also other rifles out there that will produce the same accuracy and even better accuracy for a lot less money. Savage would be the one I would pick right now for a new hunting rifle. I would get a 280 or 260 rem over the 308 as well. Flatter shooting and better down range performance. The 280 is a 7mm-06 (30-06 necked down to 7mm) the 260 (6.5-08 308 win necked down to 6.5mm) The 7mm and 6.5mm offer almost as good a range of bullets and weights as the 30 cal. But both offer much better trajectory than the 308.
This too is coming from a avaid 308 lover. Any one of the three with take just about anything on North America.