I'm not sure what Scientoligists believe in for an afterlife. And this is why I think you're judged by your own conscience. That's not the same thing as moral relativisim, because in that, as long as you can rationalize your behaviors, they're not immoral. I'm talking about what you held to be right & wrong in your heart of hearts. I cannot imagine a God with any sort of mercy or understanding acting in any other way.
But then a lot of people who are really good people but judge themselves by too high standards wouldn't be good enough for heaven. For example "I saved 1000 people from burning buildings but there was one little girl I couldn't save and I'll blame myself forever"...
Also you'll have people with really bad moral codes going to paradise. Some people are really really bad people through and through. These people would be rewarded over people who do bad deads occasionally but know they've done wrong.

Personally I quite like the Grim Fandango idea of an afterlife. Anyone who's played the game must surely agree. "The Gate opens, the Gate closes, it does not help."