The best vehicle I ever owned was a 2002 GMC K1500 SLE, ext cab, 4.8. Only A wheel hub and instrument cluster repair in 100k miles. Original brakes on it when I got the fever and traded that in on a new 2007 new body style Chevy Z71 k1500 LT ext cab 5.3. My first brand new vehicle. Days after the 36 month warranty expired I found both left and right floor boards saturated with rain water. Local dealers wanted me to write a blank check for them to diagnose the problem. They advised me to consult the dealer I bought it from to see if they would contact GM on a "good faith" repair. That small town dealer was shuttered during GMs restructuring. I drove it around for a while without carpet and padding, shopvacing the water out every time it rained. A local bodyshop claimed a faulty body seem under the wipers was likely the problem.
Needless to say I didnt have much good to say about GM but I was about to buy another GMC K2500 (2011) when the ford dealer offered me a better deal on my leaky chevy trade in.
As my 4 kids grow older and the trusty caravan odometer rolls over and over I find myself looking at full size suvs. A 2 year old, used, former rental suburban/tahoe/yukon is priced more than a new 2017 expedition mid level xlt. Im not sold on the longterm reliability of the ecoboosts.I love the looks of the durango...but...dodge, again. That leaves the thirsty japanese models (sequoia gets like 17mpg hwy??) or the sturdy, proven, push rod small block GM models. We rented a yukon xl and the wife loved it. When the time comes ill just have to hit harbor freight up for some of those cheap tarps to cover it when it rains.
Aluminum doest worry me much.
Freightliner cascadia class cabs have been aluminum. I'd say they hold up fairly well. The Grumman LLV are aluminum, they've outlasted the post offices expectations.
Many oem body panels have been aluminum. Early 90's towncars to late model explorers and even the late model aluminum bashing Chevy Silverado have aluminum hoods.