it has a ton of flaws
first of all it counts completions twice, so essentially passer rating says a completion is worth about 20 yards of offense when we know that most completions go for far less
it also penalizes interceptions too heavily...INTs are worth about -100yards according to passer rating and that's simply an inaccurate assessment considering a TD is only worth about 80
you like it and thats fine but saying it doesn't have any flaws is not correct