We use Polaris Ranger 6x6's for all of our pond work.

Pros:
- stability (side to side and front to rear)
- traction (the thing is a tank...it'll go anywhere)
- load carrying capacity (2000lbs in the bed and 2000 towing)
- 41 mph max speed
- the reliability of the polaris products

Cons:
- it'll tear up some turf in a hurry if you're not careful about your turns (all 4 wheels in the back are locked full time)

It's a great machine and highly recommended. Most of the time, our 6x6's carry a 800lb skid sprayer with 50 gallons of herbicide mix.

If you have any more questions about them , let me know. I can e-mail you pics of our "Pond Tanks"!