Absolutely true (on the advantages of not stripping to bare metal) but I would amend the point on metal etch primer to add that a good epoxy primer may be a better option. It not only bonds better, it creates a harder surface. Another nice point is that it gives you up to a week to apply the color coat without having to re-sand. During that week, you will still obtain a really strong chemical bond.
Also, rather than trying to apply a skim coat of filler, I find that a couple of coats of high build primer (like Evercoat's Featherfill) is a MUCH easier approach. It is essentially a really thick primer you can shoot directly over the Epoxy primer (I prefer Southern Polyurethane's product both for the price as well as the quality). 2-3 coats gives the perfect base to block sand to a nice flat surface, ready for color.
Also, rather than trying to apply a skim coat of filler, I find that a couple of coats of high build primer (like Evercoat's Featherfill) is a MUCH easier approach. It is essentially a really thick primer you can shoot directly over the Epoxy primer (I prefer Southern Polyurethane's product both for the price as well as the quality). 2-3 coats gives the perfect base to block sand to a nice flat surface, ready for color.
Just a point of information about your comment. You don't have to sand down to metal to have paint come out nice. In fact, in most cases that is not what you want to do. If the existing paint is adhering well, just do a 400 grit sand, preferably wet sand, primer, and paint. If you take it down to metal, you need to do a acid etch primer or stabilizer then primer before you paint. On most vehicles if you take it down to metal, you probably want to do a primer, a skim coat of glaze or bondo, then block sand to get rid of imperfections.