I tried both on the tenor.istan said:
The results are that the Rascher has a mellow smooth deep sound with some upper register brightness that the horn allows to come through.
The caravan having a little brightness to a rather dark sound "Rings" a bit and colors the sound with an annoying edge that spoils its classical sound on the Tenor, but not true on the Alto.
On the alto chu I like the Caravan as it has thicker side rails and stays smooth. On the Tenor chu the Caravan has almost the same thickness rails as a Rascher but the Rascher stays dark and mellow with a somewhat flexible voice. The Rascher maintains some resistance so one can work diaphragm pressure to build volume. A little more work than just blowing and getting sound but deffinately smoother of the two. The Rascher gives the Chu a deep low end and a dark voice, good for section work or quartet I think.