I can tell you that changing them out isn't hard at all. Mr. Swanie did it in about an hour.
The older, more "problematic" brand that we had was called "Lifesaver." They also go by the the brand name "Kidde." If you want a good laugh, read the product reviews for our old smoke detectors...
http://www.amazon.com/Kidde-1275-Bat...1030266&sr=8-4
swanie