Neither of those pedals is going to be THAT great. What amp are you using, and what styles of music do you want to play (I'm assuming metal, but there might be others in addition to that).
Ibanez RGA121 | ESP LTD H-1000
Axe-FX Standard
Want to play all metallica, and using Fender Frontman 25W, and ESP EX-50.
i can assure you that the jackhammer is MUCH better than the boss metalzone.

The chances are that the demo is based on some sample settings which are written in the manual so read the manual. This is the one compact pedal i've seen where i thought it would be necessary to read, due to it having so many controls.

If you're aware of what the individual controls do then you'll probably be able to work it out yourself from there.
I like analogue Solid State amps that make no effort to be "tube-like", and I'm proud of it...

...A little too proud, to be honest.
i was a true blue boss mt-2 lover. i would argue that it was a great untill.............i got mad enuff to go to guitar center and buy a metal muff...........holy$hit was i wrong. the metal muff beats them all hands down.