well, to be honest it really depends on if you want a manual or auto too, but the Dmax trany and motor are really reliable but not enough torqu.. the Powerstroke at 06 is a 6.0L international motor and is reliable and has plenty of power, the 07-09 is a 6.4L international motor and is okay depending on if ur planning to put a Tune or programmer in it but the 07 keep blowing the bottom end, but they have plenty of power, now we get into the New 2010 and 2011 F-250 witch has the NEW 6.7L Ford built Powerstroke and it has the most power and so far nothing has gone wrong with them, dad works for ford and he was test driving one and dry assfault going 30 or 25 he punched it and it broke the tires loose, so right there tells u they have plenty power stock, but the Cummins diesel is the best for all around, the I6 torqus up faster there for makeing better acceleration and pulling, but the Dodges tranys suck, if you get a Auto and planning to pull havy loads then be planning to put ur money in the tranny, but for the average man and all i would get the 06 F-250 plenty power and reliable, but if u want a manual i would get cummins