I think good performance SHOULD be stated so that users can know they're buying a great, optimised product. We would we point out the faults without pointing out how well the game runs? Especially since that's not a given in our day (case in point every other AAA release).
Topic on User talk:Pridit
It's simply not necessary, when you purchase a product you expect to have acceptable performance. If this isn't the case or the performance can be improved by either a patch or some other means that's when it's perfectly understandable to mention. Besides performance can be relative, it can run perfectly well for one user but another user may have multiple issues even though they meet or exceed the system specifications so unless it's cited by multiple sources instead of one user experience this can be misleading to the reader. There's much more to it than simply stating this runs well because that's subjective.
I'm not saying you can't input information about performance but ensure this isn't subjective and cite multiple sources so you can back up your claims.
After talking to Andy I've refined my approach to this. I agree a simple sentence doesn't cut it for the very reasons you mentioned, however I still think there should be a way to measure performance and overall PC-specific quality (excluding special cases that are then mentioned with or without fixes).
Andy said that a rating system might be a good approach and I agreed. We'll see how such a thing can be implemented in the future.