I've had a geekdesk (height adjustable desk) for several months, and I've really liked it.

My back feels great. I'm not tired. My legs have adjusted to standing a lot. Recently, my neck and upper back have felt really tension while using the desk. Might it be because I have my arms and hands fixed on the desktop while typing? I'm not sure. Perhaps monitor placement?

If anyone else has had this problem, I'd like to hear what you did to adjust. Any suggestions welcome.