Having used Aurora, LSP and LOR I can tell you that LOR is the most consistent and stable option. That said, the sequencing capabilities in LSP and Aurora are far superior. This is especially true if you use RGB washes, Firefly etc...
I have not used Vixen so I cannot compare it to the other three options...
As to DMX support, it is was mentioned on the aurora forum that Aurora would only support "their" DMX adapter. I have no idea if that is true or not but if it is I would be very disappointed...
LSP is making significant progress and is turning into a very impressive tool. I had some issues with it in the 09 season but David worked non stop on making it a better product and in the end it was exactly what I needed.
Frank