Are the gospels reliable? (idea)

The Gospels were not only written decades apart, there are parts of the Gospels that were added in over three hundred years later, according to Biblical scholars. What that means is that the same people that chose the canon for the Catholic Church (which led to the printing of the Christian Bible, used by Catholics and Protestants, with some minor changes, alike) looked at the Gospels (each one, scholars say, was also not written by a single author) and say, "Hey, there's something missing here."

So they added it.

This is historically and scholastically true. Kind of scary, isn't it?

So, I guess the answer to this question depends on how you mean the question.

Is the Bible a reliable history of the life of Christ?
Probably not.

Is the Bible a valid source to base religion and spiritual beliefs upon?
Sure, it's just as good as anything else.