If you'er recoil conscience then either would be a huge change from your 7mag or 300...
Inside normal shooting distances say 400 yards and closer, the diffrence in trajectory be it the 25-06, 260, 270, 7-08, 280, 300WM, etc, etc is negligable with optimum bullet for case capacity... 150fps diffrence between the lott, doesn't really ammount to much inside that, and if you think there's a huge diffrence you're kidding yourself, 2-4" is nothing, when most every one would be guessing hold over anyway... Intamately knowing the trajectory of your weapon/projectile is key...
As far as power goes, the 300WM and other mags are in a whole diffrence class than the little 260 or 7-08, you will diffenately be giving up "punch" on the receiving end... But knowing where you bullet will strike on the outter ranges of your ability will make up for "punch"...
Although not my personal prefrence for chasing after big mule deer, I wouldn't feel underguned with a 260 loaded with 120gr Barnes TSX or 125gr partition going after big muleys. Both can be loaded up around 2900fps... Which BTW is right on par with a 25-06 of like weight, and on the heals of the 270 too... And in reality, there is little diffrence!
IMO what it really boils down to is personal prefrence. They are so close in performance its really to close to call... I have a 260, and went that route because I wanted something diffrent, I've killed a few deer with it and had no problems... No moster muledeer bucks, but a good sized whitetail buck hit from about 250 yards... down like someone pulled the rug out from under him... He's was as big of bodied as most of the mule deer that are posted on here...
Good luck with what ever you decide!