Every truck has its issues no matter what the brand. My recommendation is find a mechanic that is familiar with the truck brand/engine/model you are leaning to buy and have them do a pre puchase inspection. Not all diesel guys know each engine well, so you need to narrow it down to what ones you like and one like and then go from there.
I was more flexible and used the overnall internet distaste for the 6.0 to my advantage and walked out with a 23k dollar truck for 16k which left lots of room in the budget to do all the 6.0 proofing work.