I think there are a couple of 'rules' for watching this film, to get the most out of it.
Firstly, if you came to it after watching Mangrove then abandon all expectations of a similar film, it is completely and utterly different. Not in a good or bad way, just do not expect anything remotely similar.
Secondly, be in a situation to allow yourself to become absorbed in the film. If you can watch alone, in low lighting, perhaps with a drink or two, and can leave your phone alone for just over an hour ( I know, crazy!) then you will be able to give your whole attention to the film and I think that is the way you will get sucked in and, very possibly, be absolutely blown away.
Lovers Rock is not about script, dialogue, action, character development. It takes a certain place in time, a certain moment in time, and inserts itself right into them and is about just experiencing it as if you were there yourself. It's all about the vibe, not the story. The music is fantastic.
This type of film is most certainly not for everyone, but watch it with your full attention and it might just be the best film you've seen for a long time.
Oh, and anyone who loved it should check out Climax by Gaspar Noe .... also brilliant and similar in lots of ways.