being an electronics/controls guy i know the benefits of solid state but at the same time, solid state does fail as well, the emitter/base/collector junctions can short out or open, especially power or mosfet transistors switching 30amps. even being in a very technical electronics driven profession i still believe in the KISS theory. If a relay fails, i can go down to the local store, or keep a spare with me and replace it on the spot. plus i have 2 fans so im not completely dead. if that solid state device fails....... not as simple of a repair. Just my opinion....... :P