This is likely to start the great debate, and I apologize in advance.
This 'whose is better' is similar to Ford vs. Chevy vs. Dodge. There are a
lot of people out there who swear by their Polarises. Myself, I wouldn't
touch one with a pole. I've been driving pretty much exclusively Honda dirt
bikes and ATVs since 1980 or so. They tend to be a little more expensive,
but worth it in my opinion. Today Honda doesn't make a 2 up machine, but
they will by this coming summer see
http://powersports.honda.com/2008models/#BigRed
If you are a beginning rider, and plan to ride double on anything but the
easiest terrain, I'd suggest either a side by side machine or one designed
to carry 2 people like a Polaris Sportsman Touring, or CanAm Outlander Max.
You can add a 'buddy seat' and footrests for a passenger to almost any
machine, but you affect the stability and therefore your safety by doing so.
My wife and I drive Honda Ranchers and we both have buddy seats and pegs,
but we're not hauling other adults around either. We bring our kids (8 and
12 year olds). The 12 year old is getting her own machine in the spring,
because it's getting to be too cumbersome to haul her around on the back...