The Blutsauger is not for a normal Medic that heals his teamates and only ever uses his primary for seconds at a time; this is for aggressive Medics. The passive health loss makes you regen less effectively, meaning that if you aren't landing a lot of shots, then you're wasting its capabilities and you're better off with using the Bonesaw or the Crusader's Crossbow. You want to equip the Blutsauger with the Bonesaw and the Quick-Fix so you can focus on defeating your foes instead of keeping your teammates alive. The health boost will keep you alive in 1v1 situations giving you an advantage over a lot of classes if you can land your shots. The Blutsauger shoots ten syringes per second and each one does 10 damage on average, so if you land the majority of your shots you're doing around 80-100 damage per second (which is very powerful considering that in that same time you are healing around 24 to 30 health). You can overpower most classes considering they aren't landing every single shot. The syringes arc heavily so you will need to be smart with your shooting. To be an effectively aggressive Medic you need to strafe left and right, jump up and down, and generally be difficult to hit, but doing this will make it harder for you to hit your enemies, so be mindful when doing this. Don't be afraid to switch to your melee weapon when your Blutsauger runs dry, but don't always start charging your enemy when you run out of ammo. Only charge at your enemy when you're at point-blank because the reload is quick.