The thing is, its gotta fit you and your proportions, and you and I can be the same band and cup size and the same bra will fit you but not me.
A bra that fits is comfortable, underwire or no underwire. If its uncomfortable it doesn't fit.
My advice is to go to a store, gather as many as you think you might fit into in multiple sizes and try 'em all on.
And FWIW: I have been "fitted" twice, each time I was told I was a D cup. I am not, D cups are too big and the C cups fit better. You just gotta try them on.