Ask any up and coming developer what they would like to do in the next year or so and you'll invariably hear, I'd like to become a Development Team Leader Hopefully most will have actually considered the change of role and be looking for new challenges and ways to contribute more to their chosen profession. However, for some this is an automatic response to a question that is particularly difficult to answer in an industry with no clear career path. For others it's simply a way to move up the pay scale.
Here’s my experience TL:DR; take: requires learning how to manage people, delegate. You’ll spend 80% of your time in pointless meetings and writing docs. Moving between jobs will be harder because companies are most likely to promote their seniors to TL instead of hiring and also because salary expectations are higher.