I can get 0.5" group on a good day with my Tikka T3 1:8, but the T3 Lite 1:12 is a one raggedy hole rig.

For hunting, this accuracy difference is splitting hairs. For target, it's important.

1:8, 1:9, 1:10 will stabilise heavier bullets, which will perform marginally better at long ranges.

1:12 will stabilise 55gr 223 ammo and lighter.

Personally, I don't need more than MOA accuracy (and I can't achieve 0.5" groups from improvised field positions) so I mostly have my 1:8 to increase the choice of ammo available to me.

You have to consider your own, particular requirements.

1:12 gets you the lighter range of bullets generally from 55 on down for smaller game and varmints. Don't use 68s or 69s in the 1:12 or you will get flyers and probably "keyholes". Savage makes an accurate rifle and here is a pretty decent review of the rifle in .223 and overall commentary:

http://www.chuckhawks.com/savage_edge_detail.htm