Pettitte says that he used HGH only twice in 2002 when he was on the disabled list and trying to recover from an injury as fast as possible. If this is true, I think you have to look at Pettitte in a different light than those who were taking performance enhancers and steroids to improve their play between the lines.
At the time Pettitte used HGH, it wasn't banned by Major League Baseball. So technically the crafty left-hander didn't break any rules. Too bad it's MLB's responsibility to keep ahead of the users and find out what is being used and what needs to be banned. But if HGH wasn't a banned substance in '02, you can't really fault Pettitte for wanting to get back to his team as soon as possible.
Also because he came out and owned up to what happened and what he did, I get the feeling that he will become more of a Jason Giambi than a Barry Bonds. Giambi apologized (although never really clearing stating for what) and it seems like all was forgotten about his steroid use. With Bonds, his vehement denials fuel the fire against him.
So as the fallout from the Mitchell Report continues, I think Andy Pettitte will be one of the best to come out of this. Compared to what Clemens will face, Pettitte coming forward and owning up to his mistakes (even though HGH wasn't illegal - which is Baseball's fault, not his) will most likely turn history in his favor.