[Spiros]

Difalco seem hugely popular over the pond in the USA and are very highly regarded amongst serious racers.

Indeed so!
I have owned several, including one that has been upgraded repeatedly and without difficulty over a period of 10 years. Presently one is used strictly for 1/32 with either a 290 or a 191 (referred to as the 'west coast') network. Another is used for 1/24 employing networks from 78 to 162. Unbelievably reliable and easily repaired should the need arise, and Jim DiFalco has always been willing to assist with problems and/or repairs.
NOTE- the 'pro' brake adjustment pot is problematic for 1/32 use and I would recommend the standard item