While re-validating in a 152 a few years ago I got told by the instructor not to sideslip but to fly properly. I found this bizarre as it only showed his lack of comfort in light a/c. He was a jet jockey during the week. I have several thousand landings mainly on Islanders, and have slipped it just about any way possible. When operating in strong winds into short airstrips it is important to be able to slip well, at low level, to cope with rapid wind changes if you want to be able to get into the runway you are looking at. Indeed in the Islander I frequently used assymetric power to assist with the slip when countering crosswinds. Something that no-one seems to have mentioned here is that the wing down method for off setting a crosswind is itself a sideslip. My advice is simply don't do it if you are not comfortable but a sideslip is not just a method of recovering a bad approach, with practice you can fly the approach, touch down, ground roll and take off in a slip.