What are the advantages and the disadvantages the followers of freemason get?

There is no such thing as "followers of freemason[ry]". Freemasonry is not something you follow, it is something you join and become a member of. The advantages are that you meet many wonderful people, have an opportunity to do things which are beneficial to the community, learn many interesting things about the world, find out about yourself, and gain self-confidence. The disadvantages are that it will cost you dearly in time and perhaps in money (some Lodges are more expensive to belong to than others).