I agree with BubblyBoar. Brute Justice is crazy scary if you leave it roaming around freely and not focus attack it. However, when I play as one I try to protect it as much as I can, so that it will be out in the field (intimidation) and do the most damage to the opposing side.

My game plays as a Brute Justice.
Stay behind DPS/Chasers lines. I always ask my alliance to form three lines when we push. First line makes up of DPS/Healers in the front. Second line makes up of Oppressors and/or Chasers to back up DPS and avoid range damage since mech cannot be healed. Third line is reserved for Brute Justice.

Why did I put the Brute Justice on the third line?
It has the biggest area of coverage in term of range. It does not need to be in the front to get its health zerged. Beam and Flamethrower will wretch anything in front.

A good player on a Brute Justice needs to be observance and anticipate incoming attacks/harassment of foot soldiers dps. It applies to other mech as well.