You are intellectually satisfied (even when you don't know, you know that you don't know and are intellectually honest about it) Cons: Even in the 21st Century, you have to endure bald being a hair color. How is this a religion?
Logic and reason can be the only avenue to truth. "Faith" requires thinking to stop. Probability is on your side - see Celestial Teapot. Cons: The world will look down on your amoral outlook because morals stem only from religion...oh wait, they pick and chose which morals to follow in the bible - that means morals are NOT a priori knowledge
You get to sleep in on Sundays. You can act good because it betters the lives around you, not out of fear of hell fire. Cons: Most would rather their daughters marry a member of the Taliban than an atheist. You're one of the few minorities people feel they have a moral right to hate.
Reason can draw you to this quickly. Often more sophistocated (though not inherently.) Not the choice for someone just "picking," usually. Cons: No exempt status. Rarely respected by anyone religious. Unfortunately, despised by radicals. Fox News hates you. (Could be a pro, up to you.)