I drafted up a fairly detailed post about this subject in the general forum not long ago. I'm going to copy and paste my comments about the various 2A groups, hopefully, it provides some useful insights.
Here's a link to my original post.
Who to follow/support:
Save the Second - don't be deceived by what appears to a small social media following, Save the Second is a leader on the NRA reform front. Rob Pincus, a fairly well-known firearms instructor, is arguably the most well-known within this organization. I've trained with Pincus, I've spent hours with him discussing the state of the NRA and reform efforts, and hold him and the rest of the Save the Second leadership team in very high regard. Note: Pincus won't sugarcoat things. He can be brutally honest, so if your feelings are prone to be hurt easily, consider yourself warned (this applies to all things, not just NRA matters FYI). Look to Save the Second for honest information as it happens on what's going on with the NRA.
Firearms Policy Coalition - this is where my money goes now. They're doing the Lord's work on the legal front throughout the country. They're filing proactive, Pro-2A lawsuits almost weekly in states across the country. Adam Kraut, mentioned above, moved on from attempting to reform the NRA and linked up with FPC guys. They're doing outstanding work in the courts, an area where the 2A fight is slowly morphing too.
Second Amendment Foundation - Alan Gottlieb and his team have been fighting the good fight for decades outside the NRA wire and do a bang-up job. Supporting 2AF with your time, money, or talent is far from a waste.
Your state-level 2A org - I've got a real soft spot for these folks, they are me in essence. These groups are often woefully underfunded, understaffed, and undervalued, yet their work is critical. The NRA largely leaves these groups to fend for themselves - last I knew they had 2 NRA staff members assigned to their Clubs and Associations division. 2 staffers for 50 states' worth of organizations... to me that's just bonkers. I'm biased, but I believe the states are every bit as critical as the federal level. A word of caution on state-level groups, however: there are several states where you have do-nothing groups that talk a big game about 2A rights, fundraise off of their tough talk, but fail to ever deliver any results. There's this weird family act (based out of Iowa, sadly) run by the Dorr family that starts 501c4 political action groups, takes people's money, and really does much of nothing. Last I knew they were active in Iowa, Minnesota, Georgia, Ohio, Wyoming, and probably a few other states. Point being, just because someone says the things you want to hear doesn't mean you should just throw them money when they hold their hand out (and the Dorr family most definitely will). Do a little research, ask around.
I personally don't support Gun Owners of America. Anytime there's a family element (Larry Pratt and son Erich Pratt both hold leadership positions within GOA) within an organization my suspicions become heightened. GOA is another group known for their tough talk, and while they do some things their rhetoric to victory ratio is off balance in my opinion.