I ran a quick JBM comparison and it really boils down to how hard you can push one or the other. If you romp on the 6.5 and run it 3200+ you start seeing an advantage over the 270 both with 140 Bergers, but it is very minimal at 700yrds. If I were targeting bears I would try to push a 150gr bullet out of a 270WSM.
I think the 6.5 WSM is cool but it would take more investment on the reloading bench and time to reload also. As far as bullet selection goes if you take a look the offering at best the 7mm may have one or two more bullets but in alot of selections the 270 and 7mm have three, there a alot of 7mmWSM shooter out there, I just hate anything 7mm due to some very poor terminal bullet performance, ballisticly it is real good by the numbers.
If you don't have 270WSM you owe it to yourself