I read his eBook and it really helped me out.
It may not be ground-breaking or anything, but whatever it is, it did something very important for me. It helped me realize that I need to think about dealing with girls in a more strategic and experimental way.
I've realized that I shouldn't treat girls how I'd like them to treat me, but how they'd like me to treat them. DeAngelo's book helped me with the original realization that the difference between those two things is night and day.
He also helped me understand that what girls like and what they're attracted to are two totally different things. I'm not bad looking but I've had girls like me as one of their favorite guys in the world but still not be attracted to me, and I couldn't figure it out. For me, as a guy, attraction is all about finding a girl who's hot that I like as a person--apart from the physical aspect, my criteria for a friend and a girlfriend are almost identical. I had always just assumed that it was that way for them, and that all I had to do was to get her to like me enough and I'd be set--I never realized that they have two totally different, almost mutually exclusive, types of liking. And I was doing all the things to raise the wrong one.
Since I've read his stuff and figured that out, all my past successes and failures that seemed like dumb luck before now make perfect sense.
It may not all be groud-breaking or flawless advice, and I may have learned this stuff from other sources if I'd spent the time. But, for what it's worth, he did help me.