Which do you guys think is the better bullet for accuracy and killing performance ??

Haven't really done any terminal performance testing (paper only, thus far), but as for accuracy in my 223:
1)Blitzking
2)Vmax
3)Ballistic tip

this is in MY gun. YMMV.

Also, this has been for the 50 gr version. Haven't tried the 55s, my rifle don't like the 40s.

Coot

SIERRA.... I use Sierras from .22 to 30 cal. and see no reason to change.
Stepchild

You don't state what you're hunting. I've used both bullets on varmints and deer, in different calibers of course. I've found them to function in a similar manner. The Sierra is less expensive. As far as accuracy is concerned, it varied by rifle. Some of my rifles prefer ballistic tips, others Sierras.

Bob257

For me Sierra and the V-Max run awfully close in accuracy, Sierra's a little more consistant than the V-max's, followed by the BT's.