It's not perfect, you can normally find them cheaper than the normal ones. To be a blem/2nd it is either, in between weights/a half weight, a extra long pin 5 inches+, bad coloring, and sometimes pitting of the coverstock. For the most part they are fine, they just don't have the ideal specs of the regulars. If you are cool with the weight, and that is all that is wrong with it and he cuts a few bucks off the $$ for you, go for it.
Just my ever so humble opinion.