To be a contrarian, let me weigh in an say that the big advantage to painting your model is that you can decide on the color scheme and colors you like. And....IMHO paint will outlast iron-on any day. It will not sag in the hot sun, the edges will not pull away and allow fuel and oil to seep under it, and you don't have to worry about the cowl and wheel pants matching the color of the iron-on. Does it take longer? Some say that a good covering job should take as long to accomplish as the constuction of the airframe.
One caution though. If you have never painted before you need to think out the challenges you'll face. Do you have the necessary spray equipment; do you know about masking and finishing; do you have a place to spray; and so on. If the answer to those questions is no....use iron-on. Regards.