I want a touring 2 up.  What is the consensus on the 600 vs the 800.  The think I noticed about the test ride on the 600 touring is its louder and more buzzy than my Yamaha Grizzly 550.  Any advice would be appreciated.  I am also considering a Polaris Sportsman touring 570.  Anyone with the touring long term hows it been?

My experience certainly isn't long term, only a few months.  I can tell you that I am pleased with my 800XC. I went with the 800 after reading some reviews that said the ride / handling was much better on the 800 with the suspension it has vs the 500 (which is what I was thinking about). I've only had a passenger on the back for one ride and my wife said it was very comfortable.  I had also read that the CF Moto 2up seating was about the most comfortable on the market.  It was comfortable for me as the driver to have her back there as well.  We are both overweight and it was still fine. 

One negative I will say that I discovered is that the plastics aren't as flexible as Polaris, it is not a design flaw, just my fault that I lightly tipped over in a rut.  Didn't even actually go on it's side, just the fenders hit against the side of the rut.  Cracked front and rear both.  I guess it's a price to pay for them being that nice of a looking machine with automotive style paint. 

I know it's not the info you were truly looking for but I have noticed that no one else is chiming in.  Good luck in your search and decision.

The 800XC hands down!

My wife and I take many multi-hour rides and are never uncomfortable on it.  It takes everything we throw at it and it is a pleasure to drive single rider or two up.

The 600 or the Polaris are no where near as comfortable or smooth running.