It's really unfortunate that this would be so hard to use in production due to lack of a suitable IE fallback. If a browser doesn't support @font-face, for example, you can always fall back to a standard font. For isometric text though, lack of support would likely disrupt the page layout so badly that the only fallback solution would be images.
That said, as easy as it is to think of sites where isometric text would be a cool design element, I can't easily think of an application where it would need to be actual, editable text. Perhaps if you had a heavily futuristic themed CMS site...
This site fails to use unprefixed css properties when it uses the prefixed versions, so when newer browsers view the page they get a partial experience.
Nice! This can be used to make a really cool isometric website. Something similar but in terms of isometric blocks: http://kushagragour.in/lab/isoblocks/
Looking forward to digging through the source code on this one. Pleasantly surprised that text selection with both mouse and keyboard worked intuitively and smoothly (Ubuntu/Chrome) -- usually I'd expect this kind of trickery to break down at some boring edge case like this. Same for zooming with Ctrl+mousewheel.
I'd say it may even be contributing to accessibility, precisely because of the use of CSS to achieve a desired look instead of falling back to imagery. This allows to disable styles or rather allows screenreaders to still work their way through every bit of information.
But yes, for visual readability its quite the horror. So better apply it sparingly.
That said, as easy as it is to think of sites where isometric text would be a cool design element, I can't easily think of an application where it would need to be actual, editable text. Perhaps if you had a heavily futuristic themed CMS site...