The kerning, maybe I can understand, but how is the rendering "ugly"? I don't understand. So far, I only get a very small handful of users saying this, and yet they don't have the words to explain why they think so. I don't see what makes it any worse than others with similar style to it.
Part of it's that the vertical lines are always lined up with the grid rather than being antialiased. On the surface this seems like it should be a good thing, but it makes the antialiasing stand out more than it should. Just compare it to actual Windows 8 text and you'll see there are definitely a few differences.
EDIT: You have to view the image at full size or else the down-sampling covers up the differences and makes it all look equally bad.
The fact is that it probably doesn't matter whether yours is objectively worse than "others with similar style;" the problem is that, since you're trying to emulate a particular style that people are very accustomed to seeing, any ways in which yours diverges from that style will make it look a slightly jarring and probably unprofessional. The way it is now it's sort of an uncanny valley thing where it's close, but not quite close enough, to what you're trying to make it look like.
The way I see it, if you want to avoid complaints about the font looking weird, you need to make it look either more or less like the real Windows 8 fonts.