When it was running on Sci-Fi, I had only managed to watch a few epsidoes from the fourth and finale season. I opted to pick up the entire set. Currently I'm on season 4 episode 5 Promises. I've watched them all from the beginning. It's a good series indeed. A bit of a shame the series ended.
I saw a few blurbs for the upcoming miniseries on Sci-Fi in October, PeaceKeaper Wars. It looks to be good. We'll find out soon enough.