I've used a few Hobbywing ESC's with no issues... so, yes it should do fine and at 40a will give you lots of head room if your using the stock esky 3500kv heli motor... mine drew around 20a at full pitch.

I'm guessing the BEC is seperate? does it say if it's switch mode? if so 3a will be fine... thats what I run using 4 digital servos and a 401 gyro.