You have heard the turn of phrase “business or pleasure?”, and with the B visas, you get both. The U.S. Government Department of State describes the B-1 as the Business Visitor Visa, and the B-2 as the Visitor Visa for Pleasure, Tourism, and Medical Treatment (although nobody can imagine why pleasure, tourism, and medical treatment fall under the same category).
So, if you are coming for sightseeing, holidays or vacation on the beach, amusement, to see friends or relatives, party in South Beach, to see LeBron and Dwayne Wade on their home court, or even, yes, for a stay at Jackson Memorial (rest and medical treatment), then the B-2 is for you.
If you want to skip all of that stuff and get down to business, consult and conference with associates face-to-face, attend a convention at the Miami Beach Convention Center for international yachting or marine biology, settle estate issues from a deceased relative, or negotiate contracts in person, then a B-1 is for you.
Luckily, you do not have to choose. The B-1 and B-2 are frequently issued together as the B-1/B-2, hence we can just call them the B visas, so that you can have the best of both worlds. So long as you show both the U.S. consulate at application and the U.S. Customs officer at arrival in the airport.
Moreover, the B Visas application is relatively quick and straightforward, you can use them for repeat trips to the US, B Visas can last between 30 days to 6 months and are thus flexible, there may not be any extended period of time before reapplication, and B Visas can be transformed into other visas.
Keep in mind that you cannot work or run a business in the US with only a B Visa.