But granted that, for example, ClearType font rendering is great - really better than any other font rendering technology by a mile
I disagree. ClearType is far better than the previous Windows font smoothing method (which was so absolutely disastrous that it was always avoided in preference of hand-drawn bitmaps at common display sizes), but it's still only anti-aliased horizontally.

For Latin characters one doesn't generally notice, because the majority of strokes are vertical or diagonal. However as well as the issues of rotated/distorted text, it also fails badly for character sets with a lot of near-horizontal strokes, such as the East Asian languages. Consequently Windows Japanese fonts still use the ugly aliased hand-drawn bitmaps instead of ClearType to this day, which is rather sad.

Renderers that can perform sub-pixel anti-aliasing horizontally *and* normal anti-aliasing vertically - such as those in later versions of Mac OS X and Linux Xft - produce significantly better output than ClearType to my eye, especially for the cases mentioned above. And *still*, the excellent hinting in the higher-quality RISC OS fonts allowed its non-subpixel-AA renderer to produce often better output (what, 8 years ago?!) than we have today. Boo.

We have looked at offering Cleartype rendering options, but the technical and usability issues of inaccurate text spacing and rendering are a very high price to pay.
Wholeheartedly agree. Where I'd like 'Windows-style' text (more likely completely un-anti-aliased than ClearType), for labels and mock-ups and such, I'd like it to stay consistent and not re-render when zoomed - to behave more like a bunch of pixels than the paths of today's Text Tool.

Well either that, or a tool to quickly convert a font as rendered by Windows into a vector-pixel font.

When I mentioned anti-aliasing, I was thinking like how you can set different AA settings in games - 2X, 4X, up to fancy rotation types, and even super-sampling.
Graphics card AA is a different beast to the way Xara works. The hardware options are largely supersampling-based, producing a limited number of in-between values (so 2x will never be really smooth, with only one level of shading between different colours).

Xara, on the other hand, draws the edges of objects with a certain amount of transparency. This gets you the full 256 levels of shading for free, which is nice, but has a few artefacts, like for example if you put a yellow square on top of a red square without aligning the edges to pixels, you can see a fringe orange outline.

[Feature plea: I would love to be able to export-with-supersampling from Xara, to minimise effects like this without having to export a high resolution manually and scale it down to size in a separate bitmap editor.]

So there probably isn't much Xara can do with hardware AA.