No methodology is going to be perfect in every situation. Take what can (if anything) from every new methodology you encounter and mold it into something that works for you and your team. The key concept I took from the lean movement was "continuous validation" for your ideas, like continuous integration for your code. Also known as fail faster, ship often, etc. If you're going to do something risky, measure the results and react as quickly as possible. The sooner you discover you're heading down a dead end, the sooner you can perform a course correction.