Does anyone have experience with these broadheads?  Do they whistle or hiss?  I have a package on the way and I am really hoping they are quieter than the Woodsmans and Snuffers...  

I have the 2 blades and they are quiet.  I think it is the vent that makes noises, wich I imagine is why you mentioned the vent.  Feathers make a lot of noise to though so that is another reason to get them close.

Got my broadheads today and with a little wax in the slit above the bleeder they are deadly quiet!  No more hiss...haha  Step aside Woodsman and Snuffers...the Magnus 4-blade is comin through!!!  :D