I found something my 4520 does better than my 3720........ or worse.......

Brian,
I would give the pto generator alot of thought before buying. I currently have four generators, one Hondal 2000 inverter, one Honda 3000 inverter, one Onan 5500 commercial diesel and the Miller Trailblazer welder 8000 w. The one that is used the most is the 2000w Honda, it will run about 8 hrs on a gallon with medium loads, is less than 50 pounds and very quiet. In the last two years Honda has introduced a 3000 w version of this model which weighs about 75 pounds this is another good choice. The Onan diesel genset CMQD 5500 is mounted on one of my service trucks and connected to the front fuel tank. It is very quiet for a diesel and is good for running power tools on construction sites. The Miller gas driven welder is loud, thats OK given everything about welding is noisy but it would not be a good choice for backup power because of this. The Honda 3000w electric start genset I have for the 5thwheel is a great unit too and is the quietest of all at 58db, while this unit weighs about 135 pounds it is a good choice for emergency power with longer run times. Fuel consumption for all of the Hondas' and the Onan is very low compared to using a tractor and 3 pt genset. I personally can't see running my tractors to produce electric power when so many genset choices are available. I did note the other day that the X749 is capable of running the 10,000 w 3pt genset, that would be more feasible than running a 4520 but not near as efficient as a stand alone Onan 10,000 w CMQD which will idle using .12 gals/hr.

All of that said, there are lots of good choices for generators out there and it is easy to find a good match for your application but the 3pt models are much more inconvienient than the stand alone units, give that some thought.