If I want the sound all over the house or something and I don't want to wear headphones I prefer speakers, but if I'm just singing on my smule app or something like that, I prefer headphones because they're right there with me.
I'm listening to music on a portal bluetooth speaker right now. Bose SoundLink Mini to be exact. The sound quality is great, it's more comfortable, and I'm pretty sure I'm not bothering anyone. The sound insolation in my townhouse is pretty good. I can't listen quite as loudly with speakers as I can with headphones, but it's okay most of the time.
I also keep headphones handy, though, for use on the bus, at work, and in public places in general.
It all depends on the situation. If I am watching a movie at the house, I prefer speakers. If I am working out at the gym, headphones, as I desire to be considerate of others around me. I use both all the time, just usually go to my headphones so others do not have to hear what I hear.
It really depends on the situation. If I'm gaming, either will do. If I'm video editing, definitely the headset. If I'm testing music or previewing work, I use a special set of speakers that are meant for the best sound.