12pt W looks bad if horizontal subpixel text rendering hints are used (e.g. HRGB mode).
It does look better if no antialiasing is used or with vertical subpixel rendering.
The difference is introduced by our current approach to hint glyphs for subpixel rendering.
At the moment we hint glyph and later oversample.
Unfortunatelly in case of W bottom part of hinted glyph
has contours exceeding pixels bounds a little bit.
However, oversampled contour makes this difference noticeable because
it is about subpixel.
See 6449753 for more notes on potential hinting improvements.