Is Miami a better place or San Francisco?

I am from New York and I love how lively it is, but it can be too crowed. I also lived in Machusetts, it has some lively parts but a bit too boring, not much to do. I am in LA right now, but in the southern part and its dirty and ugh. I have always wanted to live in San Francisco and I have lived in Florida (which is a bore), but never been to Miami. What do you think is best, San Fran or Miami?