Jon,
it's not an either-or proposition. Even if you mod your grill to hold a propane burner, you can still use it with charcoal only. It's a simple mod. All it takes is cutting out the propeller thingy, and bolting in the burner. You can remove the burner from the ashcatcher in 5 minutes, but I don't even bother. Just turn it upside down, knock the crap out of it, it's fine.
Personally, I would like to try the pizza insert, but no one is handing me $160 at this point.
Congrats on your new grills(s?). They look great!