The Ford Expedition EL has a nicer interior with better third-row accommodations and is less expensive, but has less power and can't tow as much as the 2500. The Toyota Sequoia offers even more power than the Suburban's 6.0-liter V8 and tows a respectable amount, but doesn't have the same interior space or hauling ability. The Nissan Armada is well priced and also has a strong 5.6-liter V8, but the interior is cheap and third-row is very small. The Mercedes-Benz GL350 has strong off-road ability, seating for 7 and a torquey diesel V6, but is more expensive and less spacious inside.
So the Suburban 2500 is pretty much unrivaled in the class of full-size SUVs with superior cargo capacity and hauling capabilities. It's not the last word on refinement and it remains cumbersome in city driving, but for people who love the Suburban for what it is, those flaws won't matter too much.