I was looking at Federal. If they're the same bullet internally, I'd say go for the lower velocity one. If the P308G (the faster one) uses a heavier-constructed bullet, I'd go with it. I note that Federal claims the E variety is for "Medium Game", while the G variety is for "Heavy Game." Hmm.
Winchester also offers two .308 180g loads, but sadly neither is the FailSafe bullet. They do have a nice Failsafe in 150g that would make a nice all-around load for deer and the occasional chance hog, but if you're loading for hog, I agree that 180s are the way to go. Winchester has 180s in both the Silvertip and the Power Point. Frankly, the Silvertip looks like the better of the two:
