Booking my room last year using the convention code worked very well for me. While I couldn't get the rate reduced for that stay, I did get three free nights and two more nights @ $50 each in October. It was the main reason I got the job that week because I expense account bill for such events. The guy that writes the checks knew I love Vegas and knew I might have some comped room time just sitting and waiting to be used.
The Riv ain't that bad. The convention block rooms are in the newer towers. The rooms really aren't as bad as some portray. ....besides, what do you do in a hotel room in Las Vegas? I sleep, change clothes, shower, shave and another "s" word. Every room looks the same when you are sleeping.