First off i had boughten a Digitech Hot Head Distortion Pedal the other day

Question 1 : Is it a long lasting pedal?

Question 2 : What settings should i put the pedal at to have a sound like Megadeth/ Metallica.

I've had the pedal for almost exactly 3 years now.
It's lasted me pretty well, except about two weeks ago the battery thing broke, but I just bought an AC adapter.
For a sound like that, I'm not sure because I'm not a metal fan, but I'd say gain around 8, high around 6 ish and Low around 8 ish

But thats just a guess off the top of my head
Check the book, it's got a few nice settings in it