There are so many coverings and methods it would make your head spin. The first thing to decide is what is your basic objective? I get the impression you want something like Monokote (no painting, less permanent). Of that type (shiny plastic look), I prefer Ultrakote but none of those are very permanent IMO and serve their purpose to get you flying. It is important to seal the seams around where the fuel will blast it so it will stay on the airplane.
Solartex is a great covering and is far and away superior to Ultrakote and Monokote. This is a fabric and has a more satin realistic look. Great for scale applications. It can be painted as well. Sig has a product called coverall which is great as well. It is a fabric with no glue, so Balsarite must be painted on to where you want it to stick. It shrinks down with heat and then needs to be painted.
The plastic films are a good compromise on small sport models as they are fast and light. They just do not last forever. At least I have never been able to get them to.