I did some comparisons using the Point Blank program and was not impressed.
270Win 130gr bullet 3050fps 250yd zero bullet hits 3in high at 150yds and 3.25in low at 300yds.
270WSM 130gr bullet 3275fps 250yd zero bullet hits 2.25in high at 150yds and 3in low at 300 yds.
I would not run out and trade my old .270 for a WSM unless it was a 7mm or 300