The rust appears to be light surface rust. Check for no bubbling, holes, cancer rust. The "rust" on the white one is irrelevant body rust, that can be wire brushed off as it appears. The scratches on the black one are significant and problematic for the future. The paint is damaged, and you may get rust in the next few years.
Similar price range, the white is the far better vehicle IMO.
* Probably a type of dignitary or similar life, due to the apparent flag mount holes, and that means a relatively easy life of shuttling people around on paved roads in ideal weather. It also means excellent maintenance with OEM parts or better.
* White has 25% less miles.
* For a vehicle of this class, and intended role, the 6.0L is a far better choice. It's beefier, likely well serviced, and the suspension will have been beefier too.
* MPGs? You don't buy a Suburban to get good MPGs. Buy a car.
$10k is fair today for the white one assuming it passes all inspections.
The black has too many issues, rebuilds, dubious maintenance, and those scratches suggest a lot of trail use which is punishing, dusty, rocky, water passages, etc. There's just too many unknowns and issues, the least of which is almost 200k miles, many of which appear to be trail miles. This one is nowhere near worth $10k. Too many problems.