Damage: 50% -> 30%
RoF: ~ -10%
DPS: ~ -35% (before -50%)
It's still an either module damage OR raw damage weapon. It's not like you can not deal module damage with normal cannons either but the splash strips MRPs incredibly fast. Don't use them for direct module damage/sniping purposes, use them to strip MRPs fast and then snipe with railguns, PAs, cannons or lasers.
A C4F HYS cannon can be used for sniping as well but eve na C3F is already meh.