I've used both and prefer RL 15....
I've used both and prefer Varget...
In my -20F tests I found Varget lost half the velocity that RL15 lost (100 vs 50 fps) and is generally as or more accurate. When I did the test five or six years ago it was enough to cause me to switch when I'd run out of RL15.
However, I'd still chose whichever your rifle liked best, 50 fps be darned...
