Rob

I bought the Denon 1602, and have no regrets.
I'm not sure 6.1 will be a huge advantage over 5.1, it's not exactly revolutionary to put one more channel in the back. I saw the Gladiator in 6.1, and didn't really hear much difference from 5.1. When 9.1 gets big, that will be a different story!

Your best bet is to listen to both on the same speaker setup with the same source, and see which one you prefer.