The market is already a little saturated, but this looks promising.
Source: code.google.com
I’ve only used Cucumber before and I love it (the Ruby version at least, I’m not totally sold on the Java stack). But I’ll take a look at Concordion.
Source: maxheapsize.com
I’m still struggling between TDD and BDD. I feel BDD is a better approach, for the tasks I’m asked to do at least. However, when I need to develop sevices to facilitate behaviors, that’s when TDD kicks in.
Source: tbray.org
Doesn’t look as fun as cucumber, but it is Pure Java
Source: jbehave.org