It would be a shit version of either of them.
And Buddhism doesn't really believe in a concept of heaven or hell, at least not how Christian cultured people would understand it. It's more to do with planes of existence that you can move up and down from depending on your accumulated karma of that life. Some believe that ghosts are on a different and lower (i.e. unhappier) plane of existence only to roam until their karma has been equalised and they may be reborn back on the Earthly level of existence.
But Buddhism is funny in that it's a bit more like a virus of a religion than something like Islam and Christianity. It is so heavily influenced by Hinduism, Chinese traditional mythology and influences from India, Russia, Japan and now the West that there are thousands of sects that believe incredibly diverse things. I'd hesitate a little even to call it a religion, it's more like a spiritual mindset which people build a religion on top of. A sort of religious ingredient which is then fleshed out by others.