I have both the Special and the Classic. Both ride like a smooth road bike more than a track bike. Both are also the smoothest most comfortable bikes I have ever ridden. Since the 1970's I've owned a lot of bikes but these are the very finest ride of all.
Although both share the same Reynolds double-butted 725 tubing, the Special is brazed lug construction and the Classic is welded. My perception is the Classic may be a little bit more responsive but maybe it's just the bullhorn handle bars.
I did a TON of research before I bought the Wabi. In my opinion you cannot buy a finer bike anywhere for the money. I did a 30 miler on the Classic today and could have kept going for another 30 miles easy. It soaks up road vibration like a sponge without feeling mushy. They have a unique ride quality that I've not experienced on other bikes. I have Challenge "open tubular" Strada Bianca 30 mil tires on the Special and Challenge Paris Roubaix 28's on the Classic. Both with latex tubes. Those tires are magic on these bikes.
Richard Snook sold Wabi a few months ago to some fellas from Tulsa Oklahoma and I bought my Special from Richard and the Classic from "Matt" one of the new owners in Tulsa. They are carrying on the high quality tradition that Richard started. Go for the upgraded Sub15 wheels. I did for my Classic and they are just unbelievable.
My Special
My Classic