Hi,
you may also consider this circuit as a 'current comparator'.
Esentially, the Vout vs Vin plot will be really similar to that of an inverter, but the triggering voltage will be shifted (determined by the sizes of the devices and the bias voltage of M2).
Really, the output is High impedance and the exact voltage will be hard to be defined.
For the small analysis itself, I think it should be something like:
Vout = Vin*gm_m1 * gds_m2
Since gds tends to be big, the gain of the circuit will be big. This means that the output is very sensitive to
small variations of every parameter, making it somewhat not useful for manufacturing (without feedback).