I downloaded the free trial of BBEdit editor and I tried it on a new MacBook Pro with retina display. Surprisingly the text looks pretty bad, like if it is not focused. I doubt this is normal. Is it a problem of the free trial version only, or a problem with the software? Is there any method to make it look like other applications (TeXShop, TextEdit, ...)?
Edit: as of version 10.5, BBEdit has retina support.
I believe it's because BBEdit, like some other applications (Chrome, to name one) doesn't use the standard OS X text rendering library, thus it doesn't automatically get the Retina-calibre text, rather the text gets scaled up (like non-retina images), resulting in the blurry look.
Luckily the BBEdit team is working on it, they've released a beta version with retina support.