Here is my 2 cents: Regarding performance between the two different element wattages, they are sized for the capacity of the smoker. Your finances will dictate how much to spend, as will the size of your son's family. Having said that, the old adage that you can cook less in a larger smoker but not more in a smaller smoker needs to be considered. Handing down a cherished possession from one generation to another is a time honored tradition. Getting something new and shiny 'just like dad's' is always is always appreciated.
Can a smoker really be called a cherished possession?