Thanks for the great info Chris; much of my work is in parks, often driving across grass and muddy places, I thought the XC-90 would cope but stupidly it doesn't have a diff lock so if one wheel spins it digs in and refuses to budge! not good when you are on your own in a darkening park!
In that case yeah makes sense! Surprised XC90 is that poor... would have thought even if electronic it would have had some trickery to stop one wheel spinning... kinda fundamental on anything even vaguely intended for off road or low grip conditions.
Or get a 2wd... spend the cash on something fun... and keep a set of snow chains handy