That is the issue I am having. Eclipse-based IDEs are not ready for Retina. The text is legible, the IDE is usable, but its noticeably blurry. I've logged a ticket with Aptana Studio and Eclipse, but they have no solution to this issue, just workarounds which don't really work.
If you are using Vim or a simple text editor, however, there is no issue with the appearance of the text.
There's another option. You can get a third party utility like SwitchResX ($, but the free ones didn't work very well when I tried them) and run your display at native resolution. Yes, you get a full 2880x1800 desktop, and yes, some things get terribly small. But, you can then set your font sizes larger in things you use all the time, and I find the really small stuff to still be readable, maybe just not pleasant for long term use.
I am running that way right now, using Firefox zoomed in slightly, and it works beautifully. SwitchResX lets you set up hot keys to switch resolutions too, so I've been switching back and forth between 1920x1200 and native resolution trying to decide what I like best. So far, I think 2880x1800 is winning, with Firefox zoomed in, and a 14 point font (Inconsolata) in Emacs and iTerm2. Though both of the latter work correctly at Apple's scaled resolutions already (I've so far settled on Inconsolata 11 at 1920x1200)
For me, the biggest thing that's changed is that I've used Monaco 9, or variants thereof on non-Apple platforms, as my code font for the last 15 years. This was already too small for some people to read, and I've had hotkeys set up to switch to larger fonts when showing other people code on my screen for years. Monaco 9 doesn't even really exist at scaled resolutions though - it is NOT the same font you get if you render any other point size of Monaco, which is what happens at Apple's scaled resolutions. "Monaco 9" looks like the rest of Monaco now. (Techincally the old pixel version does still exist when running at native resolution, but it's crazy small and although I can read it with some effort, it's not really practical). But the screen is so great that I'm finally over my obsession with pixel fonts. Inconsolata is a fantastic tiny font when the pixels are too small to see. I'll probably try a few more now that I've been liberated, that was just the best I happened to have installed already.
If you're using the "best for retina" resolution, you can get Monaco 9 on the native pixels by selecting Monaco 4.5. It will be extremely small, but if you have good eyes it should still be readable, more readable than anti-aliased fonts at that size anyway.
Hey thanks for that. I wasn't aware I could type smaller sizes into the font selector. It doesn't seem to work very well though. iTerm2 still renders a scaled font when I do that. Terminal does render the bitmap font, but bold text is all screwed up - apparently it's bolding by rendering twice, slightly offset - only that offset is now multiple pixels, so it doesn't look bold, it looks like two overlapping renders. Emacs has issues with the font selector dialog in general, and doesn't appear to accept typed values at all. Further, when setting the font the normal emacs way (using an X11-like font description), it errors out when trying to give it a font with a fractional size. Monaco 5 does work, but it's not quite right.
Anyway, I wasn't really trying to get Monaco 9 back, I'm actually happy I can use "real" fonts now and still get as much code as I'm used to on screen.
I'm curious to see what new fonts might be in the works for retina displays. Most (all?) existing fixed-width fonts seem to have legibility on low-res displays as a major design consideration. Since that factor is now eliminated, could we be in for some awesome new typefaces?
The problem is most likely at the level of the SWT library that Eclipse uses, and speaking from experience good luck getting any issue with that sorted out in a timely manner, let alone an issue only affecting OS X (Windows gets the best experience, then Linux, and OS X is a third-class citizen)
If you are using Vim or a simple text editor, however, there is no issue with the appearance of the text.
Xcode works just fine, too.