A few weeks ago I decided to try the NextDesk Terra standing desk and have been using it at least every day or so for at least an hour or so each time. Getting used to continuously standing is a different experience and results in a little more exertion. After a couple of long walks today I decided to try lowering the desk (it is motorized) and sitting at it. My first observation is that if you have a comfort mat to stand on (likely an essential when standing for potentially long periods) you should probably not put a chair on the mat. This means that you have to move the mat (and have somewhere to put it) as well as keeping a chair handy. The next related observation is that you probably have a bare floor under the desk and where the mat was so rolling a chair around on it might scratch or otherwise mar the floor (hardwood in my case). While this is not a deal breaker it is something to be aware of if you are going to try standing. If you put your desk on a carpet it may accentuate movement when using the keyboard if it is a two legged model (mine is) so it may be better to plan a bare floor space for it but I have not yet tried comparing bare floor to carpeted floor experiences.
One thing that I am confident of is that you may not be able to stand for an entire day unless you are already used to it and that might not be good for you anyway. So far I have no complaints but I still have not gotten around to setting up my home office space to accommodate the standing desk and old desk better (so it might be called “cluttered”). The issue with the loss of easily accessible storage space on the standing desk is also something to be ready for. And, as expected, my desktop might also be considered “cluttered” at this point as a result.