I haven't tried a standing desk for programming yet (it's on my todo-list).
But I did have a summer job as a student where I was standing in front of a computer all day, registering incoming packages in a warehouse.
My feet hurt for the first few days, but after some experimentation with different footwear (I ended up with a pair of orthopedic sandals as the most comfortable), a soft mat to stand on, and a 5-10 minute break each hour, I had no issues after the first couple of weeks.
I'm pretty sure that moving is better than either standing or sitting. Since walking around isn't very compatible with working on a PC, I expect that an adjustable desk is pretty much the best we can do. Along with switching between standing and sitting, frequent breaks, and suitable footwear.
My feet hurt for the first few days, but after some experimentation with different footwear (I ended up with a pair of orthopedic sandals as the most comfortable), a soft mat to stand on, and a 5-10 minute break each hour, I had no issues after the first couple of weeks.
I'm pretty sure that moving is better than either standing or sitting. Since walking around isn't very compatible with working on a PC, I expect that an adjustable desk is pretty much the best we can do. Along with switching between standing and sitting, frequent breaks, and suitable footwear.