Here are my thoughts, gathered from the other discussions:

Pros:
+Replenishes ammo at the same rate as a lvl 3 dispenser
+When Ubercharged: gives healing target infinite ammo, +15% fire rate, +25% damage resist to both medic and patient
+2 separate Ubercharges, like the Vaccinator, but 2.

Cons:
-Replenishes health at the same flat rate as a lvl 3 dispenser (no ramp-up out of combat, as mediguns do according to wiki)
-Ubercharge does not make medic or target invincible
-25% Ubercharge rate
-25% overheal rate