have had my 15' Silverado since new. no problems but a/c goes out and is a known problem that gm wont repair, very frustrating since they want $1500 to repair it. It does shift clunky and had valve failure from AFM which was covered under warranty.
Buddy has had a 16' Ram 1500 ecodiesel, with no problems but the cost of diesel + maintenance (even tho he gets 26mpg) for him is about the same as my truck running 89. His oil changes cost a fortune since it takes so many quarts. 10.5L per oil change. his has had no issues so far. Heard that ram's have serious engine problems after 130k or so miles or something, or maybe thats the HEMI.
Know someone else that needed a repair on ecodiesel engine, at around 100k or something, And the repair was like $15,000 or so. Maybe he had to get a new engine, i can't recall.
Watch out for diesel trucks with known turbo issues though, since everytime you take it in for something turbo related, will run you a lot of $$$.