Mark,
We used Robot for a while but stopped when they went to a Windows version because you couldn't format output however you wanted it. We needed this because we have special post-processing needs so we have our own in-house post-processor. We were unable to read the data into our program so had to switch back to STAAD. Since then, the guy that sits next to me has kept an eye on ROBOT and he's a big fan. He was showing me some stuff just today and it looks like it's head and shoulders above STAAD though take that with a grain of salt as I haven't actually used the latest version. One thing I was looking at was it's COM whatever it's called. Looks very powerful for customizing the program to meet individual needs. Seems to be tailor made for exactly the problem we have of wanting to do our own post.
Another problem they had several years ago was their support structure in the USA. It was awful. Hopefully, they've got that fixed. I too would be interested in other opinions.