I have a standing only setup that is based off IKEA's hand cranked standing desk (I take advantage of the empty space below the desk for storage). I started with a makeshift platform on a table to make sure it was not a fad for me before getting my current setup. I found my posture improved while standing.
Having said that, I don't know if my health or anything like that improved significantly by standing.
I love working while standing, but...
I work mostly at home (and we don't wear shoes in the house). I have a standing pad, but my heels were bottoming out to the floor and eventually started experiencing heel pain. I started wearing padded slippers on top of the pad, but by that time it was a little too late. I developed plantar fasciitis in both feet. It was worse in my left foot than my right foot. My right foot has cleared up, and I'm working on stretching exercises to help clear up the left foot and have been making progress.
I am currently using a drafting stool until my left foot gets better. I really miss standing. In fact, I'm itching to get back to standing. I will be making a couple of major changes. I now wear Crocs while standing. I get that they're fugly, but they are in my experience, the most comfortably padded shoes for the price. I use the ones designed for people who work in restaurants, and they're great. I feel no pressure on my heels when using them. I also plan on alternating into sitting a little more often.
-- Notes
If you're thinking of getting the IKEA hand cranked desk, be aware that the table top that comes with it is not solid. I originally wanted to cut a hole in it to permanently mount my dual monitor stand, but doing so would have compromised the structural integrity of the table top.
From what I gather, foot problems are common with people who move to a standing only setup, so take some actions to mitigate this if you can.