I have had a few Sony ES models. One of my favourites is the Sony 777ES. Kick ass receiver and a very under rated piece. Shortly after I got rid of it I went with a Yamaha DSP-A1 and the Sony was heads and shoulders better in almost everyway possible. I also had the 7ES and it once again was a nice unit. I have also had the 333ES and 555ES. I have never had one of the newer ones but if they are anything like ones from the past year or two, they will be nice. Up until I got my Denon 3805 I was running the Onkyo 800. Very nice unit but a little shy on power when it comes to lower ohm speakers. I looked hard at the Sony 9000ES before I went with the Denon but I just could not justify the money.
Only thing I can compare against is the 777Es vs the 800. Even with the 777ES being a few years old, I would take it over the Onkyo 800.
I guess what I'm trying to say is that both Sony and Onkyo make dam nice stuff. If your going to be powering lower ohm speakers and want it loud, get the Sony. The Onkyo will also work but you may have to add another amp to offset it.
