I've had different opinions on fonts over the years, sometimes with little to no preference and other times trying to use a single font across all my devices. I finally decided the only real preference I had was not seeing the same font all the time for a long time. Seeing a similar pattern with my preferences toward color themes, I finally decided to stop letting myself worry about it and set up [1] for my fonts and [2] for color themes. Every time I launch emacs it chooses at random from up to 22 available monospace fonts, 4 font sizes, and 38 color themes. This has proven very useful for juggling large numbers of sessions on the same desktop (especially with window translucency).

[1]https://github.com/dwringer/emacs/blob/master/.emacs#L120-L1...

[2]https://github.com/dwringer/emacs/blob/master/.emacs#L210-L2...