Switch Systems for D600?

Can anyone give a link showing this "banding" issue I hear about? I read somewhere that the issue doesn't show up in the Canon software, which is all I have used for my RAW processing, and I haven't noticed the issue. Of course maybe it simply doesn't exist on the 450D? There is too much noise at anything over ISO 200 for my liking with the 450D anyhow. That's offset by the fact that low ISO noise is minimal even at 15-20 second bulb exposures. Still, means I have to use wide open aperture, fast glass and long exposure times for decent shots of the stars. From what I have seen in the samples, I can get the same performance out of the 6D at ISO 1600 as I can from my 450D at ISO 200. This noise banding thing is of concern though. Noise becomes painfully obvious against the blacks of the night sky. Makes one develop an intense hatred of noise, heh.

And thanks to those who have replied. I have never shot with Nikon, so I really just have a good handle on what I like and dislike with the 450D, and where I want to see improvements. At the top of the list is noise and ISO range. Outside of that, linking actual comparisons is very helpful (gobiassumcoffee). Oh, and I don't mean to overstate the importance of built in WiFi. It was just one of those things that seems might mesh well with my photography style. I don't have it now, and wouldn't miss it in the future. Just the idea of it seems neat; I can see some potential.