Is typing comfortable with a standing desk? Every time I've used a computer at standing height, it's been a little uncomfortable, but they certainly weren't tailored to my height.
You really need one customized for you. It's probably worse to have a misconfigured standing desk than it is to have a correctly configured sitting desk.
Typing at a standing desk is comfortable if you get the height correct for your body. And for me it is important to have a riser at the front of the keyboard, like this [1]. My arms are angled close to 90 degrees, but pointed slightly downward, a keyboard flat on the desk would put far too much stress on my wrists.
I use it far too short a time (2 weeks now) to say whether it really helps, but it's definitely a change that makes me happy _so far_.
I feel more awake (no 'slumping'). I move a lot, walk in circles and just move away from the machine, when I feel I need to think about something.
Will I keep using it from now on? Only time will tell.. It _is_ definitely less comfortable than reclining in a good chair.. :)