Above average build quality, good about of features and pretty good for the price, the fan is 40x40mm and is really effective. However the plastic case can be a bit weak, I've managed to crack the base just from some light basing in an 1/8 buggy. also it has a relatively weak BEC, only up to 6v, so HV servos won't run great with this esc. the output wires (to the motor) are also 12 gauge, a bit less than I have liked. the on off with is also a potential long term problem as it begin to leak and also fall apart. With all that said, this is still a great budget 6s capable esc!
I'm using this ESC in my Yeti XL alongside a Leopard 4074 2000kv and it's a great set up!
Lots of power on 4s (I've not even bothered with 6s) with no cogging at all!
Excellent quality you'd expect from HobbyWing!