7 career no hitters? How about over his entire career? On any given night he was no place near Clemens, Koufax, Gibson, Maddux. On average he was 11% better then the average pitcher in the given year pitched (ERA+ adjusted for park, and per year is the single most helpful way to look at a pitcher - unless you count the stats that are associated like DERA and NERA.
Pedro is 57% better then average
Mussina 22% (twice as good as Ryan)
Lowe 19% (har har)
as long lasting physical freak he's in the top 5, too bad that isn't the same as pitching.