I have the S&W XVR 460. I say go for it. The ability to choose between 45LC 454Casul and 460 makes it very versatile. Short range training and fun shooting I use 45 LC to keep it enjoyable and then long range training I'll use 454 or 460.
LAX Ammo has 300gr 460 at 1800 fps for $1.31 per round.
Something to think about is how you secured your SxS and ATV. If you secured it by the wheels or lower suspension, it allows the SxS and ATV to move and sway. At the very end of the trailer this can increase the amount of swaying mass.
I had some sway issues with mine and I noticed the SxS...