there really isn't a most accurate mechanical broadhead. If your bow is tuned to shoot a decient hole thru paper, generally speaking just about any mechanical will fly well. If you don't have a good hole thru paper and the arrow is swimming to the target than you are not going to get the best preformance out of any head.

Just like the fixed ones the tip is a consideration. Muzzy has a triocluar chisel tip know for it's bone busting. A mechanical with a chisel type tip will bust bone a bit better than one with a cut on contact head.
Size of the blades seems to concern some. I have had good luck with the 1 1/4 inch size. Others feel it is necessay to have a larger cut. The larger you go the more KE required.

Broadheads that fly well for me after a bullet hole thru paper is achieved.
Nap shockwave, it has a chisel type tip and is a good bone buster if need be.
Nap scorpion flays well, have not taken a deer with one yet.
The smaller one inch size fixed blades fly and impact right with everything else. Nap nitro, slick trick, ultimate steel to name a few.
Magnus stingers work well for me also. I've decided to try these out of the ground blind this year.

That's what works for me, don't see why it won't work for everyone.