I own two 7RemMags (an A-bolt SSstalker and a Ruger M77) and while I have never owned a 7Wby I know it to be a great gun and have shot many that were customers and freinds/relatives guns. I personally can't see a difference between the two as far as real world killing power is concerned. The only way you will get that extra 200fps boost with the Wby is when using Wby ammo and Wby rifles. Other makers who chamber Wby calibers don't usually have as much freebore and the 26" barrels that make the Wby shine. Recoil wise, again if you are talking about non-Wby guns/ammos I have never felt the difference. A MarkV with fullboat loads does kick a slight bit more but not enough to worry about, IMHO.
Until the .270WSM came out I used to praise the .270 Wby for those looking for a 27cal with more juice than a .270 Win. But now the WSM has given an equal performer (too the 270Wby) in a cheaper package. I have NEVER recommended a 7Wby over the 7Rem. Truth be told, the 7Rem is so popular because it is THE most bang for the buck and has been for a long time (with regards too magnums and the overall price of admission).
If you have a 7Rem then you don't need a 7Wby (unless you just want another piece for the safe like myself!

). If you are looking for Wby and want something that has more umph than the 7Rem then look too the 300Wby. It IS a whomper stomper and will "get r dun" better than anything other than the new supermags like RUMs, 30/378, Lazzeroni's etc... I have a 300Wby and LOVE it, but honestly if I could only have one rifle (a DREADFUL thought indeed [:'(]) it would probably be some vintage of a 7Rem Mag.
If you are just looking for a 7mm class cartridge and don't really have to have a mag then look at the 7Rems lil siter... the 280Rem. My 280 is probably my most "comfortable" rifle (a 700 from Rems Custom Shop) and without question is my best shooter out ofa dozen+ centerfire big game rifles that I own. The 7WSM is a GREAT caliber as well, but for whatever reason it is basically DEAD! Some of the gunmakers are even in the process of dropping that round from their WSM offerings. That means ammo makers will curtail their offerings of it soon as well. And I hate that, because it probably has the most going for it (in a real world/usefulness sense).
Good luck,
RA