DEFFINATELY the 270WSM. I own one and so does my brother. Im shooting a Tikka and his is a Browning. Were both shooting 150gr Fusion bullets (mid-priced ammo with great weight retention). @ 100yards with factory bullets im getting .65" 3shot groups and bro is getting .87" 3 shot groups.
Federal Premium now offers its VitalShok in .270 WSM in a 110gr Barnes TSX Tipped Bullet running out at 3400 fps.
So now the .270WSM is that much better. You have your 130gr-150gr bullets for deer/elk/mooose and the 110gr for those varmints.