A lot of traffic is getting steered this way because this blog has become the #2 search result for the 'thumb break method,' specifically this post.
I liked the thumb break method, and if using a vertical grip it's the way I would should most times. However, I've found that getting rid of the vertical grip and going with a Magpul AFG has been the best move, for me, I could make when it comes to carbine shooting. I just shoot better with it, and it feels better.
I want to take a couple of carbine courses, as well as do a lot more shooting one my own. If this new job I just started goes the way I hope it does then both of those things may be happening within the next few months.