I only design my own now when I want something that is not available, like a .25 size 3D or a big old electric, or something really light. When I see what goes into a proper design by Chip Hyde or CPLR I know I could not improve on something like the Synergy for example.

I only buy top designs and kits that are built light and strong and keep away from these tip stalling, KE coupling, badly glued, way too heavy, mass produced planes.