When we were preparing for the birth of our son, we looked closely and the Diaper Champ and the Diaper Genie to dispose of diapers. We ended up going with the Baby Trend Diaper Champ, because it was a little less expensive and we didn't want to have to buy special bags for it. It is easy to use - you just open it up and hook a bag over the handles inside and close. (We just use plastic grocery store bags.) When you have a dirty diaper, put in the hole at the top, flip the lid and it falls into the bag.
The problem is that it doesn't do a very good job containing the smell, especially now that our son is older and is diapers are smellier. We've tried baking soda and air fresheners. We've scrubbed it. Nothing seems to work. I have a friend who gave up and keeps her in the laundry room. I think if I had to do it over again, I'd just buy a small trash can and put a new bag in every day.