6x4s are horrid for getting around. It will get you into tight spots but mud/snow will kill you period. They do have POWER probably the best worker of any UTV and I'm sure they would pull about any trailer just fine. Honestly if you can fit it in the bed it will haul it like it's not there. I had a huge cement slab that I loaded in the back of mine and it ran around like it was hardly there. That thing must have weighed well over 1k. They're slow though (18mph on my 03) but if you got work in mind it's perfect. It will tackle any hill with any load but like I said if it's at all muddy or any real snow you're stuck there.
EDIT: Oh yeah I should make mention I don't own mine anymore but instead traded it for the HPX about 2 years ago. I am more for recreational use.