Good design gives you a peak of usability and aesthetics. If you need a switch to let you prefer one over the other, then I think you've done it wrong.

Usability and aesthetics are both subjective. For some portion of the population, you will always be "doing it wrong."

Prettier? "Off" means "Make my font look as ugly as Parse's logo".

You realize it's the same font slightly bolder, right? Are you sure you scaled the image 100% to compare them, and your browser didn't shrink the image down to fit in your window or something?