I, personally, think the Channel 9 commentators are great. That being said, they would be my only reason for keeping the NRL on 9.
For mine, Ch 7 is the way to go. To start with, 7 is one nation-wide broadcaster, whereas 9 is seperately owned in the different states. I think, from memory, that SA & WA are owned by the same guy, and the rest is owned by another guy. Let alone the various WIN's and NBN's, ect that are subsideries of 9.
If 7 had the rights, they would show the NRL (coz they've got little else), they would promote the buggery out of it (look at what they've done for aussie rules & union), and the most important piece of the puzzle ... it would be shown in all states with decent coverage.
From memory, the ony reason 7 didn't get the NRL last time, was because Foxtel is partly owned by 9(or is it the other way around?), and that 7 wanted the NRL on C7 as well as free-to-air.
I live in Perth, so as far as I'm concerned, it can only get better from here.