[yutah]

the font does look thinner but I like it (doesn't look any more invisible from my eyes)

[dubcanada]

The fact that on a Mac the font is thinner makes me wonder if you can even see it on Windows?

[thaumasiotes]

Judging by my windows machine and using just my eyes, yes, it's a little thinner, and no, there's no problem reading it. The faded-grey-ness of the words "to Heroku" is a much bigger legibility problem than the minor change in font weight.