This is question we get here at RAF from time to time and it is a subject that has been discussed at Oshkosh during the "bull sessions".
     The reason for the question stems probably from the fact that a lot of your have flown C120's, Luscombes, Champs and the other taildraggers with no flaps. As you know, the best way to loose altitude in one of these airplanes is a forward slip. In a Champ, as an example, a forward slip will cause the airplane to loose altitude dramatically, yet not gain any airspeed. Many taildragger advocates will tell you that a slip in a flapless taildragger is more effective e=when trying to loose altitude than flaps are on a Cessna or Piper.
     What about in an EZ, though? Well, a VariEze slips quite well, that is, it will lose altitude readily in a forward slip. Not anywhere near as much altitude as a Champ or a Pitts. However, the VariEze has been shown to occasionally depart in a sideslip departure. In fact, RAF put out a mandatory change to the rudder travel on all VariEze's for this reason. For this reason, RAF HAS NOT AND DOES NOT RECOMWND slipping a VariEze. Actually, a VariEze and a Long-EZ, for that matter, will loose as much altitude as rapidly by deploying the landing brake and stepping on both rudder pedals (deploying both rudders) and slowing to around 70 knots and flying wings level.
     We have done considerable testing of this fact, and a Long-EZ with landing brakes and both rudders out, flying wings level, at 70 knots will loose 1200 to 1300 feet per minute. The same Long-EZ, clean (landing brake closed) in a full rudder forward slip will loose only about 1000 feet per minute. A full rudder forward slip with the brake down will generate about 1250 feet per minute rate of sink. All tests were done at 70 knots indicated.
     We can therefore conclude that although EZ's can and do slip OK, there is no point in slipping them because you can do just as well with the landing brake, both rudders and the proper airspeed and it is much safer since there is much less chance of a departure from controlled flight.