One on one, you have a chance in the jug if your gunery is half decent. Moreover, if it's a Spit/Niki/Zero/hurri you can always run away. if it's a G10/Pony/typhy/LA7 those guys usually keep full throttle and you can "outturn them" enought to give you a quick shooting opportunity.
The true jug killer is the Yak9U, or any disciplined pilot of any fast plane listed above.
Like ammo said, the bad news is 1 vs alot with a combi of fast planes and turnfighters. The jug is not fast enought to allow you to run to your buddies, nor nimble enought to allow you to "stay alive" till your buddies arrive.
Patience is the key, hardcore turnfight if in low numbers with some friends around, or dive away/autoclimb/cook diner/come back for more action.
With a 5k alt advantage and a good gunery, you can do some serious damages on 4-5 lower bad guys. Don't get greedy, run when you have to, usually works when you don't wait for the last seconds.