Airy, I really like the rendering of this Tamron. Your collection of lenses around the 50mm focal length appears to be quite extensive. Where does the Tamron sit for you?
Well, here's the list : Voigt 40/2, Tamron 45/1.8, 45/2.8 PC-E, 50/2 AI, 50/1.8 AI, 50/1.8 AIS pancake, 50/1.8 G, 50/1.4 SC, 50/1.4 AIS, 50/1.2 AI, 50/1.2 AIS, 55/2.8 micro, Voigt 58/1.4, 58/1.2 AIS.
Concerning the Tamron 45/1.8, there is a specific thread under "lens talk" with some comparisons.
In short, very clean, sharp (on Df), bokeh is rather good, night behaviour is very good. While the general contrast is less than with Zeiss lenses, the contrast is still there when the subject is backlit or, precisely, at night.
If you add VC, weatherproofing and an acceptable focus ring, it is a very good lens overall.