I would go 308 every time for a number of reasons.
And before people rubbish some of my coments I have used both in the field and fired thousands of rounds.
In fact I have used dozens of different rifles in my time and I can only say as I find
Firstly given the same gun and weight of projectile in both calibers, the 270 kicks more, it can be measured.
Having said that you dont nessesaraly use the same weight.
Now people keep telling me that 270s with mods do not kick a lot, I agree to a point, BUT just watch someone fire both standing and see what the effect is on them!
I have had a lot of serious opperations on my spine and recoil effects me in a different fashion to most,
I can fire identical rifles in 243, 308 and not suffer then or an hour later, but using the 270 buggers me up for the rest of the day.
I can go futher and state that my guns listed given weight and weight of bullet 243- 9.5lb-85/100gn, 7x64-7.8lb-130/170gn, 308-9.5lb-150/180gn all treat me the same within reason, fire a dozen shots, pack in and no problem.
Fireing a 270, 7.9lb 130gn, 7-08, 8lb-120/130gn and I am in bed an hour later for at least a day.
I know I am an extreeme and my body feels the different TYPE of recoil, but others do as well, eg my brother used to think I was dreaming about the recoil of his guns, hes had a shoulder replaced, he uses the 243 now! a good friend who has used a 270 for 40 years has just swapped to 308 for good reason.
I would happily recomend a 270 to someone whos out stalking in the highlands, or an 08 or 9x64 for boar etc etc, but once one is getting older etc, there are better choices.
Just my thoughts and ramblings
I am in the proccess of customising two rifles for myself, one a 308 the other a 7x64, both very light but with everything done to reduce recoil so that I can practice 50 rounds at a time.