As for negatives of a hydro-winch:
1) Packaging - more hoses to try to route through an already tight engine compartment.
2) Can't winch if the engine isn't running. While an electric winch can't winch long without the motor, at least if can, even if it means swapping batteries (most of use have extra batteries on board anyways
3) Leaks. Hydraulics will leak eventually. Usually not bad, but the potential for a mess is there. And if you do have hydro-boost, and your run off the P/S pump, a busted hydraulic hose means you effectively don't have brakes anymore. It takes a lot more muscle to push non-boosted brakes on a hydroboost setup than a vacuum setup.
4) Wireless remote setups are MUCH more expensive. Having a wireless remote can make some situations much easier to deal with, especially when doing multi-line pulls.