Are you looking for a distortion similar to the MT-2?
The pedals I'd look at most would be the H&K Warp Factor (the only distortion pedal I like), the Digitech Distortion Factory and the Line 6 Uber Metal.
For me, it's a no contest. The H&K (IMO) blows the rest away.
In saying that, it's difficult for me to tell you what you'd like given the fact I don't like the Metal Zone too much.
BOSS are releasing the MC-2 (Metal Core) pedal soon (if not already). We're getting one in for stock so ya should pop in and try it.
