One relevant consideration in such an evaluation is that Signal's policies with respect to various things (like percentage of income taken, initial deposit, length of program) may have changed since the program's inception. Of course, the program itself has changed since it started. Therefore, feedback or experiences from students in initial cohorts needs to be viewed in that light.

Disclosure: I share an apartment with Jonah Sinick, co-founder of Signal. I have also talked extensively about Signal with Andrew J. Ho, one of its key team members, and somewhat less extensively with Bob Cordwell, the other co-founder. ETA: I also conducted a session on data science and machine learning engineering in the real world (drawing on my work experience) with Signal's third cohort on Saturday, August 20, 2016.