boater- i am not sure how the new trans will hold up. have notseen any fail yet and they have been out for about a year now. its basically the same old trans but the engineers have gone through and made the weak points stronger. i still think the allison will be the best trans around for an auto. i would personally pick the six speed with 4:10 gears. the ratio between gears is very close. around town you only need 3rd and 5th. dodge and i believe chevy both use the new venture(new process) 6-speed trannies in their heavy duty applications. and i believe ford uses somthing of their own design or a japanese trans in their 6-speed applications. someone correct me if i am wrong there. they are the only manual trans i have ever seer with an external oil cooler and a pump similar to an automatic trans.
i also read that the oil change interval went way up but still dont recommend it. they added a PCV system to them and i believe that is the reason. if the truck is being used hard i would still go 3-5k between. if you drive it like a car on wide open highway you could probably get away with 15k.
as far as the steering issues go, in 03 they seem to have fixed that. they drive like a dream!!! 4x2 trucks have rack and pinion steering and the 4x4 trucks have a new gear that is nothing short of magic. it has lots of assist at slow speeds even with big tires, only about 2 1/2 turns lock to lock opposed to almost 4 on the old trucks. and very tight and responsive on the highway. i am gonna figure out a way to retrofit one of them on my old 96 diesel. the gears that came out on 99-02 4x4 3/4 and 1ton trucks were pure sh!t!!!!
given all that i think i would still go for the best deal