I had a professor who insisted that AMD made the best processors in the history of computing, but he was pretty weird. Most people don't need anything more than a Pentium 2 or 3... heck I know people with computers that still run off one of the old "x86" series processors.
I actually wouldn't be surprised at all that AMD chips (at whatever speed they're up to now) are better and/or faster than their pentium equivalents. When the AMD K6 came out, it tested out at notably higher clock speeds than the fastest Pentium on the market at the time. The problems arise over compatibility with Microsoft's software, especially Windows OS's. That was even true of the Celeron. The techies told me that Celeron wasn't really a bad processor, it's just that MS software didn't particularly like working with the Celeron processor.
I still wouldn't put it past Intel and Microsoft to have some sort of backroom deal that gives the Pentium chips the edge over the others with regard to how Microsoft software works with the various processors. Just my suspicion, completely unfounded on any real facts...