I think black hair is generally more attractive on people, as long as it's the right undertone (blue for cold and red for warm) for their skin tone. I have gone black before and it's the easiest color (it's basically impossible to get the wrong shade), but I prefer Lush's henna over most dyes. Dyes can be very damaging if you have fine hair or if the dye lacks a conditioning element. Lush henna is very intense, easy to use (there are loads of videos on it), and smells AMAZING. It also conditions beautifully!
Black, I think Brown hair is kind of sucky (I have brown hair). It's like your DNA said “hmm, what hair color should I pick? Oh, I know blonde, wait no black!" But it was too late so we got stuck with both but neither.
Mine is pretty dark, almost black and rn I have light brown highlights in it for summer. I don't know, it depends on what you want. Clearer hair is good for summertime, so I'd say go ahead and put some highlights lol.