I've been testing out Tag Manager for a few weeks now. If you want a free service it's good and I'd recommend it, especially if you do a lot of work with Dart,

I've been testing out Tag Manager for a few weeks now. If you want a free service it's good and I'd recommend it, especially if you do a lot of work with Dart, AdWords, and Google Analytics. If you have money to spare, though, I'd recommend another solution. I've only briefly looked into Satellite but I'd say go with that over GTM. GTM has the normal Google problem of making things a bit too complicated, while with Satellite I was confident that I could hand off the account to a less technical member of our team and there'd be no problem making changes.