Nakamichi sr-4a, vs. Yamaha A-S500

I have a Nakamichi sr-4a, but I'm thinking of getting a Yamaha A-S500 integrated. Do you think it's an upgrade, or just different? (I'll be driving an easy load, maybe Tekton M-Lores.
Keep the Nakamichi! The Yamaha is not an upgrade.
Agree with Yogiboy, your Stasis reciever is a keeper unless you are going to spend alot more money.
I disagree with the above posts. Owned both but not at the same time. I would pick the Yammie no question. IMO, the Nak is quite good but nothing too special, the as500 sounds way better than it's price would suggest. Very clean and neutral sound. It has tighter and punchier bass than the Nak and a more engaging midrange.