I have been using the String Framework on and off for a few years.  I heard about it back around 2005 or some time then.  I tried using it around 2006, but really didn’t have much use for it. But I stayed interested and would checking now and then to see the direction.
Fast forward a few years, now would be good, give or take a few months. I am working on Java applications for the cloud, and I get to play with Spring almost daily. The framework has matured so much, and so many new features have been added.  Not to mention the many new sub-projects that covers many of the other disciplines.
Like anything else, the more you use it, the better you understand it. And that either makes you like it more or like it less. Fortunately, for me, the more I use Spring, the more I like it. I have found it very easy to create RESTful applications and it is brain dead easy to add database persistence to your application. For those who use Roo, Grails, or Ruby on Rails, will know just how easy it is to follow convention and just have magic happens. Spring does some of that too.
Here are some people saying why they like spring. But if you want to learn a bit about Spring, you can start here.  I would like to do some Spring tutorial once I know the audience and their expectations. So if you don’t have time for reading or watching long videos drop me an email and I will can start working on some short-to-the-point tutorials.  I have done some at work for my co-workers and they really like the format of focusing on getting a task done and showing how to do that with Spring.