In my little experience so far i've always used checklists on the ground anyway, and air is mostly memory items. And to me the checklist gives the security that i haven't forgotten anything, it won't be the first time someone forgot to put something on for take-off and ends up a mile behind the end of the RWY. I wouldn't like that to happen to me anyway.
I can imagine it'll be a pain in the but to do them over and over again, but hey it only takes one extra minute to make sure you covered everything.
Why would the manufacturer otherwise require checklists to be on board and performed?? It's handy to just take the time and figure out what you check everything for (duh) then i think to most people it would actually become a CHECKlist not just a do list....