What is the difference between Catholics and Protestants?

Not much, according to this possible-though-not-likely convert.
http://souldevice.wordpress.com/2009/12/21/roman-catholicism-the-true-church-or-a-terrible-cult/

I really feel flabbergasted about someone taking issue between transubstantiation and the Real Presence. They're the same thing! One is just the philosophical explanation for the other. I've heard more exact terms and descriptions of the argument between the two beliefs, and the two I mentioned above are not the right ways of explaining it, they're shortcuts!
And btw, authority is the real issue, though he seems to forget all about Mary. Calvinism & Presbyterianism, I think, get around the 20,000 denomination-argument by saying they see themselves as actual full-blown churches--its involved but there it is. Basically, since they're a church they're allowed to condemn heresies, like the ordination of women and gays, and LGBT marriages.