That depends on if its a Smash Jug or Immortal Jug.
An Immortal Jug/Defense Guardian will give you hell in 1v1, Trust me.
I play a Pyro Powertech =/
So I may not be the best to comment in 1v1 Situations against other classes. Heh...
Since usually my battles end relatively quickly. Maras last a bit longer due to their immunity shield though.