I'd probably go with the plain-ol', tried-and-true, .243 Win. The .243WSSM doesn't offer, IMO, enough of a performance improvement to justify it's drawbacks (like the added cost and somewhat reduced availability and selection of ammo).

As for recoil, assuming identical rifles, the recoil of the .243 is not quite twice the .22-250 about about 3 times the .223, which is still not much but you will notice the difference. After a box or two, well, that really depends on you. Felt recoil, and the tolerance for it both immediate and cumulatively, is very subjective. Some people, like my wife for instance, don't tolerate recoil well at all, and she won't put more than about 10 rounds through my .243 M700 ADL (7.5lbs or so) before she doesn't really want to shoot it anymore. But she'll shoot her M700 VLS .22-250 (about 12lbs) all day long without complaint. Others can shoot a box of .300 RUM without flinching once (not me, and not many, but there are a few people who really don't flinch when they touch off the big boys).

Accuracy, well, the .243 Win, based on the .308 Win which is arguably one of the most accurate cartridges on the planet, shares in it's bigger brothers reputation for great accuracy. But it's really more of the rifle than the cartridge. As long as the rifle's not an accuracy slouch, the .243 will do very well. Of course, I don't think that the .243WSSM is necessarily any less accurate. Give two rifles of equal quality and precision, I would think that accuracy would be a wash between the two.

So my opinion would be that both cartridges have merit, but I'd lean strongly in favor of the .243Win. The decision is ultimately yours, of course, so pick the one you like the best and enjoy.

Mike