RE: Muzzy MX-3 or MX-4
I'd have to go with the 3 but only for the following reasons:
3 is a prime number and prime numbers are cool.
There's a sacred association with the number 3.
I like symmetry and I have 3 fletchings so why not 3 blades? (Not any better reason than the first.)
An MX3 killed my brown bear deader than snot so it ought to work on anything else you hit with it. (But it only needed to hit the broad side of a brown bear at 17 yds...)