Everyone has their own #1 annoyances with the differences in web browser rendering but I, personally, feel a particularly heavy sigh when I look at the antialiasing between them all. Firefox doesn't do a great job and Chrome / Safari need some extra love to make it real nice. Granted, it's a very picky hangup but I'm loving that this Type Rendering Mix attempts to solve the issue a little bit. It's maybe not necessary for every single project but for those times that you're looking to really drill down into the typeface antialiasing, this seems like it's worth some exploration.