Shorter barrel life, but has a slightly longer effective range than the 308, although I will probably be flamed for that. Why Remington?
Have you actually gotten your first rifle yet? Seems to me you were asking the same sorts of question just a couple of months ago. Not flaming you, just seriously questioning your credentials for dispensing this sort of advice. This is what knowledge seekers need to be very careful about the quality of advice given in free anonymous internet forums.
Effective range for what?? 308 Match rifle is shot at 1200M. You would need some exceptional hardware to make that happen in a 243. Compare the ballistics of the .308 208 Amax and the 105 6mm Berger VLD. Read about Palma shooting and Match Rifle shooting.
The flaming part will come with your question Remington as a choice. Been to a long range fullbore match lately? Actually spoken with any gunsmiths lately? more to the point, have you actually owned any Remingtons - or ANY rifles?
As to the OP's original question, It really depends on what you want to use the rifle for; both will run out of long range accuracy before they run out of long range steam in a factory rifle. The 308 is an excellent versatile cartridge that is very easy to make work if you are reloading.
The SPS 243 has a twist rate that suits lighter bullets, whereas the 308 SPS has a very tight twist which is better suited to heavy, high BC bullets.
We have seen a few fellows coming out to shoot Factory class (in "F-Class" matches) with stock Remington rifles and doing EXTREMELY well.
The 308 is a fantastic cartridge, has excellent barrel life and arguably the largest selection of ammo and bullets going. It does have a fair amount of recoil, particularly with heavy bullets, and this can cause bad habits when learning to perfect shooting technique.
the 243 has less recoil, but is harder on barrels, and in the case of the SPS you are limited to bullets that are more for short-medium range varmint hunting and small game hunting.
The Remington 700 is one of the most upgradable platforms going. Investing in one is a great choice. There is a huge Savage/ Stevens cult on this board, and much of the "advice" is about validation of consumer choices, than it is about being objective. More serious shooters use Remington actions for upgrading, and more custom action manufacturers use the Remington action pattern than any other pattern. The SPS is a good choice.