Which makes a better pet a savanna monitor or an iguana?

I have to pick one this afternoon. I want a lizard that will live long and get pretty big. I want it to be chill but i still want to be able to watch it eat stuff like fish and crickets. Don't try to presuede me into getting a different one because i only have enough money to get a savanna monitor or an iguana and some food pellets for it (i already have crickets for the monitor)