I decided to go to a fixed blade, but am unsure of which Muzzy to get. 100gr. 3 or 4 blade. Thoughts.
Iam shootinga Darton Avalance extreme set at 64-65 lbs.

Also, muzzy has practiceheads available. Are these just as good as using the real thing?

Both are great heads so it's going to have to be your decision. I used Muzzy 100 grain 3 blade for 10 plus years with nothing but good results...I can have them grouping as tight as any field head available. I don't particularly like the practice blades. Figure on using one set of blades as practice and keep the rest as hunting blades....buy yourself a replacement pack and you'll have plenty...remember, one shot and they are no longer good for hunting unless you replace or sharpen the blades....this is true for all broadheads.

I try to get the highest FOC possible with the correct tune of my setup. That said, I've been a big fan of the 4-blade 145 grain Muzzy. I also like the four blade because to me they are easier to sharpen then the three blade. FWIW, I can get them much sharper then what they come out of the pack.

I've never use the 4 blade but I love my 100 grain 3 blades.

I have used them both in 100gr. They both fly the same out of my bow. I have not killed anything with the 4 blade yet since I just bought them, but I anticipate that they will kill just as good. I second the idea of sacrificing some regular blades for practice.

I had no problems with the three blades. Tune great out to 40 yards, at least that's as far as I shot them. I like the way the 4 blades assemble better though.

I use the 3 blade 100 grain and have had great success including a complete pass through after penetration ofthe shoulder blade. My last two deer died within sight of my stand. I use old blades for practice. Just try not to shoot your own arrows with them.

i have tryed both and i really like the 3 blades

I have only shot the 4 blade but do like them a lot.

I experimented with both and really didn't find much difference in flight. I ended up with the Thunderhead only because I had a bunch of them and they seemed to group ever so slightly better from my bow. I guess guestimation would tell you maybe a little better penetration with the three blade but more cutting surface with the 4 blade so maybe more blood on the ground, if you get max penetration. Whitetails.... either head.