Hi,

the 15 does well in weak conditions. In a faster glide, the Standard Cirrus is slightly better. ASW19 and LS1-f are significantly better at 150kph and above. The 15 easier gets damaged at outlandings due to the low elevator and the airbrakes below the wings.

If you have the choice, go for a B. It has a larger rudder, simplifying aerotows on the CG hook, also improving the agility and control balance. The B has a larger main wheel and a higher MTOW. Many 15s have a rather low payload below 90kg.

Christoph