Well, the main point of social dance, is to go home with your face more sore than your feet ot your wallet, from smiling and laughing. A great many people are quite happy with this for their balroom experience, and the way to get out on the floor doing it is in group classes.
But real lead/follow and movement techniques require training, dedication and hard work with a private instructor/trainer.
So, it is wise to try to set your dance goals when you begin.
I am in the "private first" camp, but it is personal opinion based on my kind of goals.
It is not so much that there are group instructors who are "incomeptent", as inferred elsewhere - but that the things they must impart quickly to social students to get them moving, keep them happy and keep them coming back, very often involve expedients, including a lot of patternwork, that shortcut real training, and result in bad muscle memory which must be painfully retrained later, if one decides to really advance or compete. This whole matter is a can of worms, but having a better idea of what you want at the outset is wise.
Some of us have thrown away years of everything we ever learned about ballroom, and started over from scratch later because our goals changed or we were not mindful of them (and what they require) at the outset, and how to meet them.
We must remember that much of dance is opinion. Many people want to go down the floor with 30 patterns, with small steps and looking very pretty, and are in fact disappointed if they cannot. People like me would rather travel the whole floor with only 3 moves if necessary, with power, grace and technique, and we are willing to continually refine the very basics over & over again, forever.
Highly-accomplished ballroom is like a pyramid - you spend 90% of your time, money and work building and expanding the base. If you try to stick things on the sides, they will fall off. If you put wrong or weak stones in the base, you have to tear it all down. Social dancers don't like, or need, to get so preoccupied with this approach.
I always get compliments on my leading in social situations - but much of the time, I am actually following a woman who has learned patterns in social classes, and has little idea of what true lead/follow is - or could care less. I just smile and thank her.