I've had the retina display MacBook Pro for about three weeks now. FTM/Mac isn't all that bad because evidently, they use OS X's standard text rendering, and so much of FTM is text-based anyway.
Some programs, such as Twitter's own app for the Mac look horrible because even though it's text-based, it evidently does not use OS X's standard text formatting.
Back to FTM, I notice that with photos, if it's a higher resolution photo to begin with, it's fine, but if not, it looks bad. The icons across the top definitely need to be reworked, but it's not the end of the world.
The retina display is probably one of those features where Apple treads in first and within a couple of years, everyone follows suit. We've had the same basic pixel density on computers for nearly two decades now. This is the first real improvement. I'm certain that Apple will have all its computers follow suit within six months to a year, and we'll see Windows computers doing the same thing within two to three years.
Here's the thing though--from what I understand, Apple has been telling developers to make their apps resolution-independent now for a couple of years, hinting at the fact that things are going to change. For any company to not have their app ready simply shows they haven't been keeping up or just didn't prioritize the impending change.
I will say that the retina display MBP is the BEST Mac I've ever used. Last night, I needed to use my wife's MacBook Air for a few minutes, and it was quite noticeable going back to a "standard" screen. I've been spoiled by the retina display very quickly.