I wouldn't recommend those, but that's just me. I found them to be too swivel-ly and squirrelly when trying to place the tip of the blade in a precise location on the stencil. Once you get it going, though, they cut very smooth curves, but I found these to be hard to control as well. Nowadays I only bust out the 360 when cutting a bonnet-shaped frame around the edge of a disc.
I recommend, for vinyl cutting at least, the xacto blade shaped like a parallelogram (#16), instead of the right-triangle shaped ones (#11). They are easier to turn while dragging through a curved cut. My stencil quality doubled once i discovered those babies, and now I buy them in packs of 100!
We are not like those other golfers. We throw our clubs and keep our balls where they belong. -Ol' Bob