Preflighting files covers such a large topic. Are you looking for simple stuff, like image colors, resolution, are fonts embedded, etc, which without a doubt is important, or are you expecting it to look further into the supplied PDF? AS mentioned earlier, for simple preflight stuff Acrobat works as well as any other.
If however, you want to capture additional info like page sizes, # of pages, Trim, Media and bleed box info, or separations in the PDF (and even if setup with standard blend color spaces then a more robust toolkit is needed. All this boils down to what info are you looking for, how do you want to be presented the info, and what do you do with it when you have it. Using softproof tools to preflight a file seems overkill, manual, and may not gie you what you are looking for