Ive always said that dodge doesnt know how to make a good truck but they know how to pick a motor, and i drive a dodge.
Of course watch out for the automatics in any make, they are all crap unless its a allison but then you have to watch out for the early duramax engine blocks, they are known to crack due to heat issues.
Also look at how much repair costs are on each vehicle before you buy. If you plan on any uprgrades (injectors, turbo, ect.) look at those prices too.
For example: Cummins aftermarket injectors-$500 (estimate)
Ford Injectors (around the same horspower)-$1500 (estimate)
Cummins are all around cheaper to maintain and upgrade compared to ford and chevy, plus you get the great sound of a inline 6 and not the gas V8 sound. Oh and remember that the cummins is a 5.9l putting out as much power and torque as a 6.6l and a 7.3l V8. If you buy a Ford stay with the 7.3l, dont buy a 6.0l or a 6.4l they are crap.
Now as far as problems with the trucks themselves:
Dodge has a few problems. The trackbars are a early wear item, unit bearing front axle, and the CAD front axle are all problem areas. Also the interior is ( dash, plastic parts, ect) arent up to par with the other makes.
I only know of one ford problem in there front axles the bearing are becoming an early wear item. There may be others if anyone knows chime in.
Chevys are pretty good that i know of, i just learned about a transfer case problem they have, something inside the transfer case causes a rub in the case which eventually rubs a hole in the case and causes a leak and most of the time the dealer is not fixing it right.
Im not trying to talk you out of a Ford just trying to give you some info on the big three makes that might help you make a decision hopefully some others will throw out some more info and not just talk crap.
With that being said i have a '95 Dodge Cummins and i love the truck (even with the little problems). I would suggest anyone looking to buy a diesel to strongly look at the dodge, they are a good workhorse, mine is a testimate to that.