Honestly, if you just have 3 kids to haul, minivans or a sedan are a better choice. The Durango is essentially built on the base of a truck, so everything is more expensive for maintenance. The Durango is generally a good vehicle, but there are a few issues that are a bit like gambling. There was a known issue with the transfer case speed selector that has a small chance of shifting into low gear while moving, which can grenade the transmission and the 4.7 as well as 5.7 have the potential for dropping a valve or lifter slap.
I bought my 2005 about 5 years ago with 135k miles and I have since replaced the shift motor, valve covers, cat converters, fuel pump, alternator, the exhaust rusted out twice, and every single component of the suspension system except for the lower control arms. Meanwhile, my 2002 Lesabre has only needed an alternator, ignition module controller, and a radiator. I will say that I put my 5.7 Durango through hell and its still reliable, but as you can see from my repair list, I have spent easily $2000 on repairs and I did most of the work myself.