I've had 3 Excursions (have a really large family), two with the V10's and one with a V8. OMG, the V8 was like an afterbirth that lived in a vehicle that size! It constantly wondered shifting to stay in the little engine's power range and on long inclines on the interstate it sounded like it was pegged on the red line, tach wise, all the way up the hills. I honestly consider a V8 in an Excursion a mistake.
The V10's have been great. People tell me that they tow well, but all I ever tow with mine is a couple of Jet Skis; not hardly any test. The HUGE difference is in driving them. With the V10, they almost never downshift on highways and are the smoothest running engines I've ever owned. Weighing just over 8000 pounds, I can get almost 16.4 MPG on the highway if I set cruise at the speed limit. If I want to run with the fastest traffic, I'll get right at 13.3. If I drive 100% in town, I get right at 10; sometimes a little more, sometimes a little less. Towing, I can't tell ya. I can't tell the Jet Skis are back there. Never had any trouble with either V10. The 3 valve (like what you're looking at) has a bit more power and gets a little better fuel economy. Good sound engines.