I have a 62", 42# Whip HS, and "test drove" a 60" 46# Whistler. Both have the typical excellent feel the Toelke's are known for; smooth draw, whisper quiet, easily tuned, and quiet feel in the hand on the shot. Biggest difference for me (other than the 4# draw weight, which is noticeable for me) are the grips. The Whistler is contoured closer to a "pistol grip", with a slightly higher wrist, while the Whip is a very repeatable locator, but a slightly lower grip and a bit more "blocky", for lack of a better word... though still a very natural feeling locator. Both were classic, leather wrapped grips.
When I was talking to Dan, he said the Whistler shoots faster than the Whip for an equal poundage. The 46#er shot my Doug Firs, around 11gpp, amazingly flat and quick. The Whip is no slouch with the 11-12gpp's either, and very quick and flat with the couple of 10gpp Spruce's I have in my quiver also.
Seemed like the Whistler came to anchor a tad quicker; maybe my imagination, or maybe the more forward riser.
Long story shortened... very similar in shot quality; different grip styles; and the Whistler just a bit faster.