I've got an 02' Cummins, came in a Dodge wrapper. Standard shift so no worries about auto transmissions, wouldn't own an auto behind a diesel, just to expensive for my taste. As you said, everyone has their own opinion and I could sit here and tell you how awesome the Cummins sounds with dual straight pipes, how the Cummins is a real diesel by comparing piston rods and seeing how the Ford and Chevy rods are like play toys compared to the beef the Cummins has. I could say how funny it is to drive by the Ford boys and Chevy guys at the fuel pump cause my truck, at 9500lbs still gets over 17mpg putting around town and better going down the highway. Drove an f550 for two years(someone else's) and that thing was getting 7-9mpg!!!! No wonder the tank was so huge. I could say how I can have my valve cover off in about 5-10 minutes.....ask the Ford/Chevy guys how long it takes them. I can have my turbo off in an hour if need be, Ford/Chevy. My cylinder head can be pulled.......without having to remove my cab. I can see my inner fenders.....and down to the ground. Got 146k on mine now, have not done an alignment, front tires are fine. That f550 above, new front skins at 25k and when I was laid off from the company it had 55k on it, know what? Needed front tires. Guess I've been pretty hard on Fords but if there was no Dodge/Cummins combo, I'd be in a Ford, they have some HEAVY DUTY trucks that is a fact. As far as Chevy goes, I wouldn't give cup of warm pee-pee for one of those, but that's just me.
But, as I said, could talk all day about how I love my Cummins but you'll have to do the research and decide for yourself. Get on a couple of these diesel forums, Dodge, Ford and Chevy and see what's going on as far as problems and things like that. A Ford that would be great for putting around, 99-2002(?) the last of the 7.3L Powerstrokes. One of the best darn diesels ever put in a pickup....next to a Cummins of course(lol). I see you have heard about the 6 Oh-No!! Good, they make great boat anchors, flower pots.......new Cummins blocks.
The newer transmissions are supposed to be better, think the newest is the 68re? 6 speed? I'm not real sure. A buddy of mine has an 05' with auto and spend around $3-4k on the tranny, runnin' a bit over 500hp though. If your gonna add toys and gadgets to boost power remember this, "you play, you pay". Hope my mindless ramblings have helped.......maybe a little...
See, I can't give you an honest unbiased opinion. Here's some links,
www.cumminsforum.com
www.dieseltruckresource.com(cummins)
Ford
http://www.powerstroke.org/forum/don't have nothing on Chevy......