It really all depends on level of experience and the situ... so we are referring to your average Mandalorian warrior versus your average Jedi Knight.
If we assume that both of our combatants are experienced and at their peak in skill and physical capability, with access to their traditional armaments meeting in an unprepared fashion I say the outcome is unsure...
Does the Jedi reliance on using only the Lightsaber decrease their chance of victory when faced with an arsenal of different gadgets and weapons (flamethrowers, rocket darts, poison gas, explosives, projectile weapons and more...) ?
Certainly from an ethical standpoint a Jedi is bound by his or her code, which dissallows the use of the Force to directly harm a foe, a Mandalorian is bound by no such code and may be as ruthless as necessary to secure victory. As a counterpoint the Jedi has the Force and all the abilities that it endows.
I don't think I could claim to know who would win, but it'd be one hell of a fight!