RE: Digital or Coreless...
I used to buy Futaba 9202 servos but have had a 50% failure rate on the pots. They wiggle finding or trying to hold center. The S-131 was much better. I just bought some Hitec 6635 karonite digitals and really like them. The 6635s are smooth, strong and seem to be a good digital replacement for the S-131/9202.