Debian's release cycle still isn't as predictable as Ubuntu; in fact, Debian slipped a bit with wheezy. Whereas lenny and squeeze came out in February of 2009 and 2011 respectively, wheezy didn't come out until May of 2013. I appreciate that Debian took the time to get it right; still, Ubuntu's greater predictability is appealing. Also, Ubuntu offers official backports of newer kernels to LTS releases; that's why Docker, for example, can target Ubuntu Precise.