For the purposes you state, search out a good copy of the 75 Lux and get one that's 6 bit if possible. I spent over a year finding mine ... a late model German with factory 6 bit coding. In the process of selecting a M75mm I also sent for, tested, and rejected 3 different 75/2 ASPH ... including a new one. All of them needed to be calibrated for focusing, and when focused properly felt to clinical for my tastes.
So, I subjectively tend to agree with Denoir, and I do not agree that the 75/2 is like the 50/1.4ASPH.
The 75 Lux has some of the properties of the Noctilux other than bokeh ... like excellent flair suppression in low light with bright areas of illumination or spectral highlights. IMO, the 75 Lux isn't just a portrait lens, it's an excellent pictorial optic with a range of characteristics rather than the same character at every f stop.
It doesn't require being shot at a close distance to provide those characteristics either. When shooting really close I never use f/1.4, usually f/2 or higher ... but at f/2 shot close, the bokeh is beautiful. At a reasonable distance f/1.4, 1.8, and f/2 provide enough DOF and below f/2 gives you some additional shutter speed to work with in lower ambient when shooting at a distance.
I use a 1.4X Mag for this lens and the Noctilux. I shoot various f stops depending on the subject and lighting and haven't experienced focus shift when doing so. There is some CA but it is the type easily corrected in post, and isn't any more apparent than with some of my faster "modern" lenses.
Since there are plenty of good portrait examples posted, here are a few "pictorial" applications of the M75 LUX.
-Marc