Which is better, formal or informal education? I suppose it depends on what you're trying to learn. If you want to know something that is regular and formalized - like how to write Haiku - a formal lesson in which the rules are provided is quickest and easiest. Informally reading a bunch of Haiku until you figure out the rules is a good exercise, but messy and time-consuming, and doesn't guarantee that you'll learn the rules at all. You might come up with different rules; or decide you don't like Haiku. On the other hand, I would imagine that free verse can be written without much formal knowledge of the "rules" and precedents. Formal instruction might actually limit the creative process; a prospective poet might try to emulate what they have read rather than simply writing what feels right.
Informal education, i.e., experience, might teach one guy that all poetry is crap. For another, experience might add a richness to the sentiments in a poem that would never be found by taking a class in poetry appreciation.

I have thought for a long time that the reason we are here is to "educate our selves". This world is a wonderful school - all that limits us is our ability to perceive what is right in front of us and our willingness to accept the lessons that are offered. How to best go about getting educated is a very important question, and there are a couple things I would like to drop into this conversation that I think are pertinent.

First of all, I think it's important to remember that formal education is based on a system built around someone's perception of the way that the average person learns best. Different institutions use different systems based on different perceptions. Finding the right system for you at any particular point in your development is an education in itself. But if you find the right system you can get a pretty average education.

I think an important element in deciding how we want to educate ourselves is how we think. How we think is bound to effect how we learn. We learn how to learn as we grow up. And our earliest lessons effect how we choose to learn throughout life. We learn by exploring, we learn by listening to those who know, we learn by trying things out. What works best for us this time is what we will have the tendency to use when we need to know something next time.
The linear thought process around which formal educating is done seems to be based in cause and effect learning that begins when we are infants. A baby cries and gets picked up - simple cause and effect. If the results are consistant the learning is more effective. If the next time that baby cries he or she is ignored or scolded or beaten, the cause and effect relationship begins to break down and the lesson gets lost or muddled. I believe that has to effect how that child will learn later. Schools (at least most of our schools here and now) are based on the cause and effect model - the scientific method; as long as we can repeatedly show that this leads to that, our system of formal education works pretty well. Since not everything in this world follows a clear cause and effect path, our schools don't work as well in teaching non-linear stuff.
. Whether schools deal well or not with non-linear, luckily, our minds can deal with the messy kind of thought processes necessary very well. We can link ideas and idea chains together to come up with all kinds of conclusions that are not expected. A lot of our experience-based learning is like that. Something is going on, we think we know what the outcome will be, and BANG something totally unexpected happens and suddenly we're thrown out of the linear path that we were on and we're off to somewhere new.
The trouble with learning like this, is that we don't know where we're going, or what we'll learn. We may not even be willing or able to accept the lesson at all. Fortunately, the lesson doesn't go away. A lesson gets stashed away somewhere (in our brain? maybe, maybe not) and can be accessed, or just pops up on its own, later on. It's an amazing process and a beautiful thing. Sometimes, if we're not careful, we learn stuff we didn't even know before! Or anybody else, either! Imagine that.

Sorry to ramble on, but this is a fun subject. Have a wonderful day, everyone.