Hey,
I had the 605 in mind as my next receiver, but after comparing how it sounded against the 805, the 605 was very disappointing.
I went to a Fry's and was listening to Polk RTi 10's (the purpose for the visit was to see these speakers) with a Marantz receiver.
I happened to ask the salesman to swap to the 605, and there was a huge difference in the sound.

Then asked to swap to the 805, much better.
I could not believe the difference between them. I thought the 605 was set differently from the 805, but the salesman said both had identical settings, and added that there is a BIG difference between these two Onkyos, something not so evident with Marantz's upper and lower lines ("Yamaha has big differences between their lines, just like Onkyo").
Has anyone listened to both the 605 and 805?
I'm still wondering if there was something wrong with the 605, or if that's the way it sounds.
Please, help!
Thanks!