My middle name is Andrei and I'm a female. It goes very well in my full name and I'm happy that it's not my first name. In my language it sounds kind of feminine, but I don't think it would work internationally. I was named after the nobel prize winner, Andrei Sakharov. It's a very handsome name for a man, I think.
I'm very fond of this name, personally. I recently read War and Peace for the first time, and Prince Andrei was my favorite character. It feels like a very sturdy name to me. Not too feminine, but also not too overwhelmingly "Grr, I'm a man". I would consider it for my own son, but probably as a middle name.