I have used one of the 7mm versions, a very accurate gun and a very hard hitting round. Not so cheap to shoot though, even reloading. The .270 is a VERY nice round, easy on the recoil, common enough that its easy to find ammo for it. Not as much power as some of the larger rounds though. The .243 is just as nice to shoot, and just as accurate, but again it lacks the power of some of the other rounds. The .300 is a real hard hitter, also accurate, but again not as common and more expensive to shoot. I'd have to agree overall the .308 is probably the best all around choice, maximizing the power/accuracy balance. More common than the .300 or the 7mm, not as common as the .270 or .243, easy to find reload supplies and cheap enough if you go that route. The .30-.06 is probably the most common round, easiest to find ammo, cheapest and easiest to reload, just as powerful as the .308. Downside (to me) is its a bit harsher on the felt recoil, and (IMO) not quite as accurate as the .308.