For some, the choice of a font may not be a big deal. But to us, it’s an integral part of the interface. In OS X Yosemite, fonts have been refined systemwide to be more legible and consistent across the Mac experience. You’ll notice a fresh, new typeface in app windows, menu bars, and throughout the system. The type looks great on any Mac, and even more stunning on a Mac with a Retina display.
Yes, the right font is a big deal for me as well but no, the new type does not look great at all on my non retina displays, quite the contrary.