I think the performance is there, but with only a couple factory loads out there, what if the load you want to use doesn't pan out well in your rifle. I've seen rifles just not like certain factory loads before. The .270 and .308 have many good factory loads to choose from and at least one of them is going to shoot good through your rifle. Thing is you are comparing the 140 (7mm) to 130 (270) and 150 (308) bullets. These are on the low side of the sectional density ranges for the calibers. When and if you get into larger game like say an elk, you are going to want to step up the sectional density on the bullets a bit, which is where the 7mm-08 starts lacking. Almost no one loads anything bigger than a 140 grain bullet. The 150 grain bullet is loaded by several manufacturers in the .270, this thing has a high sectional density and will penetrate deep. You can't even find factory loadings in that weight really in 7mm-08 which is a wider bullet, meaning even less sectional density. You can find good 180 grain loadings for the .308 which come out to about the same as a 140 (270).
As I mentioned in previous post, the 7mm-08 is real nice, but there aren't any real heavy factory loads out there, it is best suited for handloaders.