Pros: +4 Stickys out at a time; +30 Health bonus from healers; +25% reload time; +25% explosion radius
Cons: -25% damage; +5% more damage from stickyjumping; Ammo works similar to spys deadringer (it doesnt reload itself it just doesnt get everything out the ammo-packs); -25% healing from healpacks

Note: not all of these need to be used at the same time, it can be that the health bonus is missing or the explosion radius etc. you get it.