Re: 6.5x284
Tough call. 308 is a good caliber, but it just doesn't hang with the 6.5-284. There is just no comparison. The 308 is like a go-cart, and the 6.5-284 is like a formula car. There really is that much difference between the two.
As for reloading, brass is nearly the same cost for both, and you should be able to get nearly the same number of loadings out of either. Powder charge is within 5-10% of one another, so again, there is really not much cost difference. Same goes with bullets. Bottom line is that ammo cost, when you load your own, is about the same. However, as mentioned above, you've gotta factor in the cost of barrels. If you figure that a barrel costs $350, and getting it chambered and installed is another $300, that means each shot in your 308 costs about $0.16 in barrel costs ($650 for barrel installed, and 4000 shots). Whereas the 6.5-284 will be more like $0.65/shot ($650 barrel installed, and 1000 shots).
Of course, barrels can be purchased pre-chambered for the savage, and are a bit less expensive, and don't require gunsmith installation.
Also: A gunclub buddy has a Savage F class 6.5-284, and shot his first barrel out at ~750 rounds. He called savage, complained that it wasn't shooting anymore, sent it in, and they replaced the barrel for free. He's now about shot out the replacement barrel - and about to complain to savage again. We'll see how that goes.
If you're in the market for your FIRST target rifle, I think you should choose a 308.