Used to have an ML - loved it except that it cannot do exposures longer than around 1/15th in dim light with fast film (ASA 1600) - the longest possible shutter speed is dependent on the ASA set for some reason, so sold it. The lens is WAY sharper than the XA's with a a bit more contrast, and about as sharp as the XA2's, but without the vignetting that you get wide open with the XA2.
If I remember correctly, the ML takes a more common battery and has AE lock by pushing the shutter button down half way, which the GT lacks. All these Minoxs are very prone to shutter magnet failure, so be prepared to waste some money on bad ones. I have owned 4 such cameras in the past 30 years - finally got sick of their un-reliability.
I now use the XA2 and two Contax Ts.