They pulled the plug after Season 4. Got pretty good ratings for a Sunday night show, I think ... but with the stunts and effects, it was apparently a bit on the expensive side. These days, its in reruns on several channels.
I think the cast still does USO tours together. My father ended up on a flight from Kuwait to DC (via Germany) with most of the cast (Haysbert, Patrick, Martini, and Irby) a couple of months back.
SnakeDoc
Also on Netflix. Such a good show.