I agree with Cari that he could get the part cheaper if he looks around and using original parts would be my first choice. He needs to have a keen eye and match up visually what he has with what he's buying. This is a nice opportunity for you to teach him about hunting for parts!
In the meantime so far as choosing...I would want both! I HAVE both and they are excellent machines. Do they come up often in your area? Things around here can show up all at once too...might not see anything good in forever and then 2 or 3 I really want all show up at once. In the times I have tried to just choose one, I've regretted it.
Right now I would say the choice is made for the 401 until he has the parts he needs for the other.
