I'm a British Freemason. I joined because I was intrigued as to what it was about, and my old school had a lodge for past pupils. In England there are many lodges for different groups of people. In the city where my lodge meets there are other school lodges, lodges for musicians, farmers, university, rotarians, scouts and those who have been a Worshipful Master of a lodge along with lodges that have a more general makeup of members.
Masonry is founded on 3 principles; Brotherly Love, Relief and Truth which can be loosely thought of as Friendship, Charity and Self Actualisation via being a good citizen / considering your role in society. Through tradition it is a necessary requirement that you have a belief in a Supreme Being, but in most jurisdictions, that belief doesn't necessarily have to conform to any prescribed or organised religion and the Supreme Being is referred to non-specific ways such as The Great Architect of the Universe. Conversations around Religion and Politics are forbidden in English lodges as they are the two main topics which divide men.
All prospective members have to express an interest in joining, and in some jurisdictions that can mean anything from the extreme of having to ask 3 times before being acknowledged, to in my own jurisdiction, you can sign post you are a Freemason and what it's about, and wait to see if they express an interest in finding out more.
As the worlds oldest and largest fraternity we have a lot of tradition and there are 3 ceremonies that every new member goes through. These are allegorical and are a bit strange to understand at first, but certainly nothing to worry about. All the rumours of nefarious deeds and devil worshipping etc are a load of crap (and I say that as the current Worshipful Master of my lodge who is about to be appointed as a Provincial Officer).
If you are looking for friendship with people from all walks of life, enjoy tradition and ceremony and consider yourself a good man (or woman, as there are lady masons too in England under a ladies only Grand Lodge), then freemasonry might be for you. On the flip side, at least in my jurisdiction, freemasonry is dying off as the older members age and less younger people join. Freemasonry has just celebrated 300 years of the formation of the world's oldest Grand Lodge. Freemasonry will keep going for many years, but in the future it will consolidate.