I can echo both of your experiences. I'm mostly self taught as a software engineer. I switch to mathematics as a major after my first year in Computer Science.

I can echo both of your experiences. I'm mostly self taught as a software engineer. I switch to mathematics as a major after my first year in Computer Science. I did take intro to programming classes and other computer science related math courses but never got pass that stuff. Without books I would have huge gaps in my knowledge. But I'm a technical book addict. I've often ended up in some trouble at the end of the month due to buying to many $50+ books. But my career depended on it. I like the fact that books give a good overview of subjects. Even if you don't remember the little details, at least knowing something exists helps when you look for a solution to a problem. That's the biggest drawback I see whit just trying to learn online from blogs and free books. But I will say there are a few really good book on that lists. Some that I've paid a lot to get.