ZupAir produces one of the nicest flying wings we have seen. The Z1 offers outstanding glide ratio, sink rate, energy retention and handling. The high performance is achieved through a careful optimization of sweep, taper, airfoil shape and twist.
The First + may be just a bit more wing span then the Mefisto, but this is a much more substantial plane designed for slope fun. A slightly longer, but much beefier and more robust fuselage, and a faster and stronger 2 piece wing.