I'm sure I miss something here: On _some_ (or most) fonts, the OpenTK TextRenderer seems to leave out the blank spaces (see attachment). For "Times New Roman" it is ok. For "Arial" its not. (Both labels get the same text in the 2nd line).
Also, in the picture, one can see those strange artefacts like ugly tiny lines disturbing the letters (some, but not all 'e', even 2 through the 'm' of 'Roman'). What is causing those?
The problems do not depend on the font size.
Yes, I cache the glyphs using TextRenderer.Prepare(). Running on Windows XP (.NET2.0). OpenTK Version 0.9.0. Using a fairly cheap onboard graphic. Newest OpenGL hardware vendor drivers installed.