BLHeli_S is new major version of "industry standard" BLHeli firmware specifically ported to STM BusyBee chip. It is a good old BLHeli in its all goodness just adds the hardware PWM and faster operation. BLHeli_S ESCs can still be configured with BLHeli Suite software and 1wire passthough from flight controllers.
Sunrise ESCs are known for the reliability long before the BLHeli was mainstream. The new BB2 based BLH_S ESCs are no exception.
This ESC is for you if you'd like to experience what the lates hardware and software has to offer in terms of flight characteristics and performance. 32khz motor update rate together with 8khz gyro and PID operation = ultra crisp and smooth operation. The ESC is easily one of the lightest 4S solutions currently on market - the majority of the weight is saved from the cables, but also the weight of the PCB and components per single ESC is at the lower side of ESCs currently available.