You sure it was the U joints and not ball joints? The ball joints were the main problem on the new style Dakota. The automatic tranny isnt the best on the market but so far mine hasnt broke yet, 94,000 miles. I just need to change the fluid and filter once it starts shifting funny which is about every 6 monts or 12,000 miles. I have a 99' club cab 4x4 with V8.
A friend of mine has a 97 V6 with 125,00 with no problems other than 2 sets of ball joints. I'm on my 3rd set too! He has a standard transmission so i cant comment on how well the auto holds up.
I bought mine because both the Ford Ranger and Chevy S-10 was several thousand dollars more. The Dakota was bigger, faster, more powerful, more comfortable and overall better quality IMO. Other than afew quirks i'm happy with the purchase and the 7year 100K warranty didnt hurt. ;) I'm looking at a quad cab Ram 1500 now.