http://www.broadheadtests.com/FEATURES.html That's 5's website.
4 Blades are not an issue unless you live by the rule of thumb that 2 blades penetrate better than 3, then 4 etc....with good KE you won't have any problem with penetration. If you found a great quality head like Muzzy and have them nailing takes, stick with them.
The only issue I have with one of your statements is....
Always comingback to mechanicals fro accuracy.
I know what you meant but if a noob reads it wrong, I'll simply say.....mechanicals are not nor will ever be more accurate than a tuned, match fixed blade head. If one can drive tacks with either style head, both are as equally accurate when set up properly. Too many jump to mechanical for a fix all out of a badly tuned matching bow/arrow combo.
Not all mind you, many shoot them out of a perfectly matched tuned set for cutting diameter or other reasons. Thank you for letting me blabber.