Both are synthetic oils. I wish I knew where Polaris gets their oil from, for all we know it could be Mobil oil. Just as long as it has the proper API service rating and is of the proper viscosity it doesn't really matter which brand you use.
I use Amsoil
F4S 0W-40, it has both the proper ratings. My 800 calls for 0W-40 with SH API rating. Its a wet-clutch compatible oil but I'm sure it doesn't hurt anything to use it in an engine without a common crankcase/gearcase. The main difference between an oil meant for a wet clutch and one without is the lack of "friction modifiers".
Use the oil you want. Some guys don't mind spending the extra money for the well known name brands. There are quite a few of us that use Mobil and Amsoil though.