Great question, and for everyone the answer will vary. Obviously, I will answer based on my opinion. As far as advantages, I see far more of those...which is why I made my choice. I like the idea of raising my own children. In daycare, they spend more time with someone else than with their own parents. If they spend most of their time with me, I am able to more effectively teach them the morals and values I want instilled in them. The time children are small is so fleeting that I want to maximize my time spent with them. They grow, learn and change so fast and so much when they are small, so I feel it is important that I am who is there to help them learn and grow.
Of course, this is not always possible, and I respect that. It is not easy to be a stay-at-home mom in this day and age. As a single income family, it is difficult to compete with all of the double income families out there, and subsequently, society's assumption that most people make that much. That requires a lot of sacrifice. Another disadvantage is when you are the primary care taker, there will be times you wish you could just drop your child off at daycare...such as when you are sick or have appointments of your own. You also do your "job" 24/7. Where people at an office have breaks (lunch, etc...), you rarely do and are even "on call" almost constantly. It can be overwhelming, but with a strong support system and friends or family who are willing to babysit sometimes, it is not bad. It can also be frustrating when people assume that because you don't have a paying job, that you don't work. I would argue that a stay-at-home mother works harder than any of them!
I don't feel there is a right or wrong answer in general. It all depends on what is right for you and your family. Whatever decision you make, if it is based on what is best for you and your children, it will be the right one!