APT will hopefully come along soon and give you his opinions, but for the most part I think he really likes his 2500 Suburban with the 6L/6speed.
My van has the same engine and transmission and I absolutely love the set up. My trailer has an axle weight around 6400# and tongue weight of about 800# and my van tows it with ease, even with the 3.42 axle.
I know the V10 is a good engine, but the 6L/6 speed combo is going to tow what you have and even larger with no problem and give you better gas mileage while not towing. My wife gets about 15mpg daily driving and we get 17-18mpg on the highway.
Good luck with your decision.