I have been using Directory Opus for 2 months and I think it is great!
I do have one nagging problem. I use FTPVoyager from rhinosoft and when I want to drag a file from the remote FTP window in FTPVoyager to a local Directory Opus window, I get a DragDrop folder instead, with a FtpTree.tmp file in it... If I drag and drop to an Explorer window, I get the file. This is only in Directory Opus that I have this problem.
I wrote the folks at Rhinosoft, and they did not know much of what to do it appears.
I use the Directory Opus FTP also, but use FTPVoyager for many things.