I've had very good luck w/ the Steelheads. Tough as nails, very low profile, and the 125s have a good 1 & 1/4" cut.

The Steelhead 100 has some issues with thread length. Some arrows it will barely screw into, if at all. Like Matt said, it's only a 1 & 1/8" cut, and like him the biggest reason I like mechs is the large cut. I also prefer a bigger entrance hole, so I want something that has "legs" on the bladetips to catch and open quicker upon impact. Steelheads don't quite have the entrance holes due to no "legs", but the exit holes are scary!

There are alot of good mechs out there these days. Since your draw length and poundage is on the "mild" side (not low, but not "hot" either), I'd say stick with something with around 1 1/4" cut and one of the new cut to the tip heads. The Scorpion XPs from NAP, the Rocky Sniper (actually I think the Sniper is 1 & 3/8" to be exact), etc. That new Jackhammer w/ the 1 & 1/4" cut should be good too. I've had good luck with the older 1 & 3/4" 100 grain Jak-Hammers. SCARY sharp blades, and BIG exit holes (again though, no "legs", so the entrance wounds are not quite so large).Rocket has a new series of steelheads this year with a cut to the tip head too. I think a Steelhead with that tip would be an excellent setup.

At the same time though, if it ain't broke, don't fix it. If you are shooting Muzzy's with great accuracy and are satisfied with the performance, why change? My only beef w/ Muzzy has been (lack of) blade sharpness and (lack of) blade thickness, but I shot the 90 grain 4 blades back in the mid-90's and was very happy with them otherwise...they killed deer and flew great out of a very hot set-up (for the time)