I had the same choices in mind you did and I went with the Honda Pioneer 1000/3.. I've put 2500 trouble free miles on in the last two years with her.. Put about 350 of them on out in the Dinosaur country and up in the mtns, rest were flatland coon hunting in the midwest FWIW..
If i was going to go with a belt driven machine it would be the Yamaha.. I had an 07 Rhino that was a tank and a solid machine, but tippy, loud and not the most comfortable.. Being said, the Viking is a big step up, but still a belt driven machine.. My only concern on that platform.
The Honda: Great machine and the reliability is great and it's about bullet proof if you aren't stupid or unlucky
. Been both on the same trip before, but not with the Honda!!
Honda Cons: Loud and hot, same as all the rest i have ridden in (Yamaha, Polaris, Kawasaki to qualify) unless you've added a sealed cab, heat and air or heavily modded the engine compartment.. I put a significant amount of reflective foil insulation under and behind the seat, added a vent with a cover for cold weather in the firewall and the machine is tolerable for noise and heat now in the summer time. Great in the winter.. Took about four hours of packing, stuffing, cutting and tweaking.. Makes the machine a whole lot better. I've ordered a set of tube style doors for warm weather that will finish the process off.. I have a soft cab on mine and it exacerbates the negatives in warm weather.. I run a split windshield to boot to get airflow thru the cab in summer. Cold weather and coon hunting the soft cab is a life saver and quite enjoyable.. I run a Mr Buddy golf cart heater in the cab if I'm sitting for any time period and it's real cold.
