I might be unique here on my experience. I have two - 2004 k2500 8.1L Suburbans currently. Both are even white! The only difference between them is one has the lift gate, the other has the barn doors.
Both will open while hooked up to my trailer. I do have an electric jack that is fairly short on my trailer. Close, but it does clear.
Not sure which one I like the most. It is nice to use the barn doors because you can open only one side. I never have bumped my head on the barn doors (I am tall). It is nice to be able to pop the lift glass on the tailgate version and put stuff in the back. Or open the lift gate and be able to be out of the rain while loading groceries. It is easier to pull the burb into the garage a bit further and still be able to get in the back with the barn doors, the lift gate requires much more room to open it. Visibility with the hatch is better due to no center obstruction. hatch also has a windshield wiper, which is nice. Groceries that have shifted have never fallen out of the back when I only opened the hatch glass. I have had some 2 liters roll out when the barn door is opened up and explode. That was fun, mainly because it was my wife and not me who opened the door.
they both have pros and cons. I guess if I found the burb I wanted, I would not let either option stop me from buying it. Then again, I have proved that by owning both I guess.
Oh, and rust not sure. My 94 had doors, never rusted. My 99 the tailgate bottom rusted out and I had to replace it. 2004 both are rust free, one is not driven on streets in winter as it is left hooked to the camper for mobility.
Good luck
2012 Puma 31dbts TT
2004 Suburban 2500 - 3.73 - 8.1L - 4x4
Helping global warming at 496 cubic inches per revolution!