Greatest lesson I think I've learned? I guess I have two:
1. Don't pay new prices for this stuff because the mark up is ridiculous.
2. Everyone is different and has different tastes so reviews must be treated as such and not as gospel truth. (Also, just like any other forums, n00bs that haven't heard anything will recommend things just because they've read about them a lot or the item has a certain amount of presence)
Hopefully my next greatest lesson is that the er4p has enough bass for a normal person like me!