The problem with acetic acid (vinegar) is that it stinks. Phosphoric acid doesn't stink, and furthermore when you dilute it you're left with phosphate which is a yeast nutrient.
This is why Star San is such a great product, it's basically phosphoric acid with a little bit of surfactant to help it along.
So many people try to skimp on sanitizer, and I don't know why. It's one of the cheapest parts of homebrewing, and it's also one of the most important, but easiest, to get right. Just grab some Star San.