Onkyo Receiver

Hi all

 I am currently using an Onkyo TX-SR577 receiver with my Q accoustics 2000 speakers. I have a chance to buy an Onkyo TX-NR609. Would the 609 give me much better sound with my exisiting speakers ? Im not sure how much better the 609 would be.

My Blu-Ray is a Panasonic Panasonic DMP-BDT310 and I am only putting the audio through my receiver so that is not a consideration for me.

Thanks