They're more of a hard-line, no compromises on gun rights as compared to say, the NRA. In some states, they and their affiliates (direct or indirect) are more successful than the NRA, in others, the NRA has the upper hand. They aren't so into education and training like the NRA is, they're basically a one-issue group...the Second Amendment issue.
They're politician ratings are more honest IMHO because they don't really get into being "access oriented" and as such, they don't owe anyone any favors or play "lesser evils". I prefer their style to the NRA's, and I get legislative and important alerts typically 24-48 hours faster from the GoA than I did with the NRA. However, just joining either or even both is never enough. I suggest that either way, you initiate and maintain contact with your elected officials and send them letters or e-mails about issues important to you. The GoA prefabs letters and e-mails for you for this very purpose in regards to gun rights. The dialogue with elected officials is more important IMHO. Anyway, the GoA has served me well, I would recommend them to anyone interested in gun rights in this country.