I have been a GunBuster fan for a small while now, but I never got around to watching Diebuster. I finally watched it tonight. After the first 3 episodes, I wondered if there would be much of any real tie between the two other than some obscure references (I got a huge Chrono Trigger : Chrono Cross feeling). But wow. The ending literally gave me chills. And I grinned ear to ear when I learned the origin of "Nonoriri" in the flashback of Nono in the comet. Overall, much better that I thought it would be. I can't wait for a thin-pak DVD set.
Thanks to the people in this thread for convincing me to watch it.