SSKaug stated the features of the new BLHeli_S program in the above thread as:
"BLHeli_S is an improved version of the base BLHeli code.
BLHeli_S delivers a throttle response that is Smooth as Silk, and the main factor contributing to this, is that it uses hardware to generate motor PWM. Two MCUs support this for BLHeli_S, namely the BusyBee1 at 24MHz (EFM8BB10F8) and the BusyBee2 at 48MHz (EFM8BB21F16).
BLHeli_S will have the same good Sync holding properties as base BLHeli. Maybe even better.
BLHeli_S generally does Startup better than base BLHeli.
BLHeli_S does damped light. Only.
BLHeli_S has motor PWM that is Synchronous to the MCU master clock, as it is generated by hardware. This makes the motor Silent.
BLHeli_S has very Small throttle Steps. The resolution varies between hardware configurations (MCU clock speed and driver type), and is between a nominal 512 steps and 2048 steps.
BLHeli_S supports very high motor Speeds. A BB1 MCU will support 350k erpm, and the limit of the BB2 is not yet known, so the code is set to limit at 500k erpm.
BLHeli_S supports regular 1-2ms input signal, as well as Oneshot125, Oneshot42 and Multishot. Autodetected when the ESC sees an input signal.
Last and by no means least, is Simplicity. If you have a regular setup, just install and go fly (calibrate if your throttle range does not match BLHeli_S default). Or if you need to configure or update, just do so with the Simplicity offered by connecting to your ESCs through the FlightController, using BLHeliSuite and a USB cable."