We have 529's. Our kids are young, so we haven't tried to withdraw yet, but since we have funded them early, we anticipate that we'll have significant tax savings, so hopefully that will outweigh the hassle.
You have to evaluate whether there is any benefit to using your state's plan. There is no benefit for our state, so we went with Vanguard's plan (Nevada). They have target date funds or you can choose from several Vanguard funds. I believe that there is also a money market option, so you can shift money to the money market option as the kids get older if you want to minimize risk. You should confirm that they do have a money market because I am not positive about that.
You'll need to find out whether one child can have more than one 529 if your father already started one for your son. You may also want to make sure that between the two of you, you don't over fund and wind up with withdrawal penalties and taxes if that is a possible concern.
You might consider searching the Bogleheads forum for more information and posting specific questions there once you've learned more about them. There are many threads on 529s there.