I built a 260 Rem for my wife and she loves it. She's killed several deer & hogswith it using Sierra 120 gr Pro Hunters and 120 gr TSX's. I use it for coyote hunting quite a bit with Sierra 85 Gr HP's.
As a sniper I wouldn't choose a 260 Rem over a 308 Win though. I've been using both for years in handguns and rifles. I really like them both but always opt for 308's on heavier gameespecially atlong range.I get as much velocity out of my 308 pistol, with 150 gr bullets as I get from a 24" barrelled 260 Rem with 140 gr bullets.
6.5 cartridges have really become the fad in the past few years, especially since the 260 Rem appeared. I think they're over rated.