The size of the Bluetooth speaker is a key factor. You will want something small and portable if you are looking to buy a Bluetooth speaker. However, smaller speakers tend to produce lower sound quality than bigger ones. While mini Bluetooth speakers can deliver a much better sound quality than what you would expect, there are still limitations to their sound. It's important to find a speaker that is both portable and lightweight, that can produce good sound while still being compact enough for people who travel a lot. Your budget is also a factor in choosing the right portable Bluetooth speaker.