BW400CN is a C-41 process film, that is developed in color chemicals and printed on color paper, sometimes you'll get a color hue or tone on the paper.
I'd go with T-Max over BW400CN, it doesn't have to be done at a "special" lab, just a lab that can develop TRUE B&W film.
I have used some BW400CN and did not think that it was that bad, for what it is. I was lucky with the first two rolls by knowing the woman that works at the place where I get film done. She said that the chemicals in the machine were fresh and it would be no problem. The last roll had weird hues to it. (Same place, different employee)