We use RTB, but we don't really use it for deployment per se - really it's just for versioning. Our deployment system is an unbelievably complicated organically developed collection of tools written in various languages by many people over many years, and we have 5 (or so) full-time people managing it. We deploy to (I am guessing) around 50 different environments, with major releases a few times/year and incremental fixes almost every week. Our code is 97% Progress but we use nearly all the different Progress products - eg. WebSpeed, Open Client, Telnet clients, Windows clients, WebClient, batch programs, daemons, etc.
I guess how you would deploy depends hugely on your level of access to and control over the target systems. In our case, we almost always own them, and if not, we have wide-open root access and log into them all the time. Other folks, of course, just package code up and send it off for a customer admin to install. We don't do that
I wish we could simplify and streamline our deployment system - it's fairly reliable, but it seems to take way too many people and at that, often way too long to get WIP pushed to test systems. Unfortunately, it's hugely critical and hugely complicated, and there are a million more pressing priorities, so, it is continually pushed to the back of the stove.
One thing I have to say - I have mixed feelings about RTB, and I don't think the fact that it was written in Progress should be relevant!, but that aside - all the time I here people say stuff like, "XXX would be so much better if we used [insert name of tool that they used at university here, eg. Git or SVN]". I call total BS on that! What problems we have are, IMO, 99% orthogonal to the tools we use. But maybe that's just us. On balance, I would put switching to a different tool at the bottom of my list of deployment improvements!
