I despise "cutesy" names for grandparents. I don't know why....I guess because I hate baby talk in general.
My grandparents were Grandma and Grandpa and Grandmom and Grandpop.
My parents call themselves grandmom and grandpop to my son. He is too little to speak yet, but he will be encouraged to do the best he can with their names until he can say it properly.
The issue is on my DH's side. There are two nieces already and they both call the grandparents Nana and Pop Pop. I hate both names and have yet to refer to them by those names in front of my son. I think we will try to just keep it grandmom and grandpop on both sides for simplicity....hopefully our son will stick to that and not use Nana and Pop pop.
(oh, and my husband referred to both sets of his grandparents as Mom mom and Pop, which I also don't like).