The EXCURSION is big and bulky for one thing, and the 4X4 won't go into most standard garages(this is the reason I didn't buy one as I won't own something too big to go in my garage, I gotta be able to do my own wrenching). Also the EXCURSION is HEAVY! It requires either the diesel or V-10 option as the V-8 is working it's tail off just to move it around pretty much. I know they are rated at 920 GVWR, but the 4X4 diesel weighs in at 8200 empty. So you really can't legally put alot of weight in them. The 4X4's also have ALOT of bad driving problems with them due to the springs that FORD put on them. Ford put stiffer springs on the X that allowed it to sit lower, but it also caused alot of BUMP steer and just an all around poor ride. Putting SUPER DUTY springs on it and new style bump stops corrects this, but will lift it about 2-3 inches. The rear springs are also VERY stiff and are known to have a harsh ride to them on all models. As you can see I did ALOT of research into the EXCURSION before I finally decided to keep my SUBURBAN and make it what I wanted.
In the 2000-2002 SUBURBANS you can get them with either the 6.0L or the 8.1L. The 6.0L is a good engine that gets decent milage, but it will know you have that much weight back there. The 8.1L is harder to find, but is one SERIOUS powerhouse that they say will still pull down decent MPG's if you can find one with 3.73 gears. The SUBURBAN will still fit into most standard garages, and there is no comparison in the difference of the ride in the two.
A V-10 or diesel EXCURSION is more than capable of doing the towing job and being a good family vehicle, but having ridden in both the SUBURBAN wins hands down in just the differrrence in ride.
If this won't be your daily driver, then I would reccomend looking for a late 90's 2500 SUBURBAN with a 454 in it. They can be had with low milage for VERY decent prices right now, but you won't ever get good MPG's out of the old 454. The 6.5L powered ones are also out there if you want a diesel, but if you go this route there are some upgrades I would reccomend to you right off the bat to keep it running(and there are some years I would stay away from in the 6.5 unless the engine has been replaced).