Well, I had hoped that the winter dirt/sand/salt would just fall off my Blackfired car! Alas, that is not the case. And that slick feeling finish is no more 
I could not stand the filth so I ran through touchless car wash, and the crud just does not come off clean. Meguir's FI did not seem to work very well with the Blackfire, but that might just be a temperature issue (below freezing here).
The Blackfire QD did seem to work better, and I thought restored the slick finish... but then ran in the slop again and the slop seemed to BOND to the surface.
I have no experience with Zaino or Klasse in the winter slop so I cannot make a comparison, but I can state a deep sense of dissapointment. I suspect Zaino or Klasse would not fare any better in this environment, but if it warms up enough I will probably try Zaino again.

I could not stand the filth so I ran through touchless car wash, and the crud just does not come off clean. Meguir's FI did not seem to work very well with the Blackfire, but that might just be a temperature issue (below freezing here).
The Blackfire QD did seem to work better, and I thought restored the slick finish... but then ran in the slop again and the slop seemed to BOND to the surface.
I have no experience with Zaino or Klasse in the winter slop so I cannot make a comparison, but I can state a deep sense of dissapointment. I suspect Zaino or Klasse would not fare any better in this environment, but if it warms up enough I will probably try Zaino again.