Hey, thanks for checking out my post.
The glass is not that heavy and adds not too much, the ergotron arm holds way more. The slickness is probably a matter of preference, I got so used to it, the regular surface feels unnatural to me. The other pluspoint is that the nibs don´t wear off. I had one on the cintiq 13hd in use for around 1 and a half year - not that it matters much...and I work fulltime on them