Ihave to be honest, the only reason I started shooting Grim Reaper mechanicals is because the bow shop that I went to told me they worked well and flew like fieldpoints. I tookthe guysadvice, and it turns out he was right. I have not had a moments trouble with them, I don't have a o-ring, and I don't have to look at the blades when I take them out of the quiver.
I don't think that I have put myself through any issues with them, if I did feel that way I would probably switch to something else.
Having said all of that, don't a lot of "professional" hunters use mecahanicals? Yes they may be paid to use them, but they still have to kill deer to remain relevant in their profession so the mechanicals must do their job right?