Having owned several .308's, .30/06's, ect. ect...
I prefer the 7mm08.
I can't tell the difference in the deer hit with it. It kicks a little less (hard to relate with 7lb rifle-Rem. Mod7 w/20"bbl).
At 300yds and beyond, the 7mm08 wins the ballistics contest. Even with a 20"bbl, my rifle gets advertised or better velocities for standard 24"bbls per my and other chronographs. Sufficient for me to forego rebarreling to either .284win or 6.5-284 as was my original intents when buying the gun. Made "mistake" of shooting it, and chronographing factory and handloads...
Although accuracy isn't too great with this gun (a fluke, others I've shot and loaded for are tackdrivers....), call it a 1.5-2.5moa rifle, it's a "keeper" nonetheless...
I like the 140gr for all uses I've had occasion to use it for, including elk. (Nosler Partition 140gr).
If I could only have One rifle, this would be it........
Be sure not to "scrimp" on the scope, and don't get too much magnification. I've got a Leupold Vari-X III in 2.5-8x on my Rem M7 7mm-08, and it's my favorite scope. I've also got two Vari-X II in 2-7x and they are close 2nd's.
However, if you're trying to save a little money (hence the XL7), I'd get the Nikon Prohunter in 2-7x, or 3-9x. Nothing cheaper than this, though......(Much prefer these to the Leupold "Rifleman" and VX-I's).