The bottom line really just depends on what you want to buy. High end Savinellis and High end Petersons are comparable pipes when it comes to quality and value (although very different when it comes to shape, system, etc.) However, lower end Savinelli's simply blow lower end Peterson's out of the water. When you hold a low end Pete in your hands you can tell that it is cheap, and you will occasionally find QC problems. Not to mention, Savinelli in general dominates Peterson when it comes to the variety of shapes and finishes available at any price point.
There is a lot of support for Peterson when it comes to system pipes and silver mounts, which is valid, but I would encourage you not to forget that Savinelli also makes dry system pipes, and does some great work with silver mounts as well, although certainly not to the extent (quantity wise) that Peterson does. In fact, there are very high end sterling spigot mount Savinelli's on sale on SP right now for as little as $120. I own two of them, and they stack up against any silver mounted Peterson.