Is that just due to the difficulty of buying them, or do builders go with older model ESCs 'cause they see them in existing bots? I know the Sidewinders had a chequered history but at least Robotpower replaced the first batch free of charge. Here is Australia, the small Scorpion ESCs have been popular and reliable.

Another new ESC option is the RageBridge 2. If you use 4 pole Ampflow motors, you can drive one motor with a RageBridge in bridged mode. Less current handling than a Vyper but better than the Vantec RDFR47E at a much better dollar per amp.