You need to figure out what attributes you value most from a car. Is it just speed or a combination of a bunch of things that make your car special for you? The B5 S4 is widely known as a budget speedster. If you value speed more than anything else it is a great car to own. Personally, I would much rather have my 13 second B7 than any (save a few stage III widebody avants out there) 11 second B5. Its just a matter of personal preference. I value the style, sound, interior, DD dynamics and fit and finish of my car. Many B5ers on the forums have a hard time understanding this and I don’t blame them because they value the thing(s) more that make the B5S4 special to them.
btw The S/C’d B7 RS4 will dominate all soon enough. It will be hard to argue is superior attributes in all categories…except, of coarse, price