[BTirish]

It would seem that you are asking for a full apologia for Christianity and a full set of criticisms of Scientology, or vice versa. This is a little beyond the scope of a reply on an internet discussion forum. Your having made the demand, however, does not in fact place the burden of proof on the believer. I've sorted these things out for myself, and I'm happy to help others sort them out as well, so long as I'm not expected to write a book before my comments are even admited to the discussion.

I could just as well assert that there are sufficient practical reasons that can be given for why it is a good idea to believe in the Christian revelation, and place the burden on you to tell me why this isn't so. This is no less fair than the demand that you have made after you flat-out assert that there is no "evidence" for the Christian revelation.

In other words, there are better starting points for fruitful discussion than the one you propose.