During my initial training slipping was the preferred method on the tailwheel trainers, but we were taught the crab method too, mostly to use it in the initial phase of getting lined up. Moving on to bigger and heavier singles I still prefer to slip, whether it's in a low wing or high wing airplane. I was stunned to discover that the man who did my chechout on the C177RG Cardinal didn't know the technique: WHAT THE HELL ARE YOU DOING?!! he screamed at me when I "established" wing-down on final in a brisk crosswind.
Slipping is still my preferred crosswind technique. I never thought of it as something that is more difficult to do than crabbing; in fact I find it easier and I think its advantages outweigh its disadvantages.
YMMV. What is important that you can land safely, regardless of technique.
Disadvantages:
- greater side loads on the aircraft and control surfaces that may have load limits, such as flaps, particularly in turbulent/gusty conditions.
- loss of lift due to yaw component, requiring a higher approach speed.
- increased stall speed, requiring a higher power setting.
Advantages:
- early alignment with the runway
- control all the way down without big changes at the last minute
- good "feel" of the wind all the way down
- reduced risk of traversing on touchdown and putting side loads on the gear.
A greater rate of descent can be a disadvantage as well as a great help. The limiting factor is the ability of the aircraft to bear side loads with effective control surfaces to keep the desired flight path. I was once told by an airline pilot that the best way to get down fast on loss of cabin pressure is a controlled sideslip. It works for small aircraft and at lesser altitudes too, but you have to keep inertia in mind -- it takes time for an airfraft to come out of its slip so the load must be eased off in time or else it can be a very hard landing!