Here’s my advice: go to the local drugstore (Walgreens, Target, etc) where you plan on buying trash-bag refills and see what brand(s) they regularly carry. DON’T buy a brand of diaper pail that you cannot easily buy bags for. The last thing you want is to be special mail-ordering your diaper pail bags.
We have a Diaper Genie II. It works great and best of all the bags are carried at the drugstore down the street from our house, as well as Target.