I'd echo what Aubrey said about ammo availability. If you're going to shoot casually with it, you're probably in good shape. If you're burning through 500-1000 rounds every month or two, and not handloading, ammo might be an issue.

I don't know enough about the 7mm-08's ballistics to know how it would compare to a .308 at long range. The lighter bullets will shoot flatter at common hunting ranges, but I don't know how they'll hold their velocity at long ranges (say, 800-1000 yds). Once bullets drop through the sound barrier, they tend to do things like keyhole, and this degrades accuracy. heavier bullets for a given cartridge, even though slower at the muzzle, tend to hold onto more of their velocity as range increases. (For example, 175gr .308's tend to hold their velocity better at 900-1000 yds than 168's, even though the 168's have a higher muzzle velocity.) You might see something similar with a 7mm-08 140gr vs. a .308 175gr. I do not have any experience with the round to verify this statement, so I'm not putting it out there as an incontrovertible fact - it's just a consideration that would need to be taken into account when working at long ranges.

Other than the above, I'd say that if your rifle works well for you at the ranges you normally encounter, and ammo availability is no problem, then have fun shooting!