Re: BOSS metal zone MT-2 pedal???
What kind of amp and guitar are you playing, and for what kind of music?
My buddy has a .50 cal and a Les Paul. We went out looking for a nice distortion that would not only drive the power tubes into a bit of clipping and compression but also add a nice crunchy sound to the mix. Our favorite was the Fulltone Distortion Pro ($220), followed by the Fulltone OCD ($180). Nothing I played came close to these guys, although I hear really good things about Rocktrons (haven't played any though).
The Distortion Pro has a great deal of flexibility, and is more a "distortion" than an overdrive pedal, meaning it's going to change your tone and give you more of the preamp edge to your sound. The OCD isn't quite as flexible, but still sounds great, and can be backed off as more of an overdrive as well. Both have plenty of gain (enough to do some metal), and responded really well to playing; pinch harmonics were a snap and they were feeding back like a real tube amp when cranked.
Either way, these are hands down my favorite distortion pedals. I can't stand the Metal Zone at all; owned it for a couple years and sold it. It's buzzy and fake sounding and ruins any tone you might have had. Just because you're playing metal doesn't mean you shouldn't have tone. Try one of the above pedals out; they're dead perfect for heavy rock and metal (and the OCD is perfect for just about anything).