There are a lot of speakers for sale with Bluetooth connectivity. They come in all types and sizes and different price points.
Like with everything else, there are compromises when it comes to different needs. There are different ranges in capabilities, sound quality and volume, as well as battery life and so on.
Sound quality in small speaker packages is a tricky engineering concern. It requires learning about a number of audio drivers and their types. Usually, the more audio drivers of different types, the better the sound quality.
For portable speakers, the number of hours of use between recharging is also important. Longer use between recharging means that there is more time being away from a power source, and longer listening time.
For use outdoors, you would also need protection from environmental factors in the form of water resistance, and shock proofing. You should be able to drop the speaker at a reasonable height, and it should still be working fine.
Besides portability and battery power, durability is another characteristic which consumers want. It also happens to be harder to quantify. For speakers used outdoors, there are standards that manufacturers should comply with. These include weather resistance and armor.
Taking a speaker when camping or fishing would need environmental protection to ensure that the speaker works even in dusty or wet environments Listening to music for hours or days is not a trivial task. Most speakers have only a few hours of playing time.
This is a function of the size of the battery, and the power requirements, as well as the sound volume. Few speakers last 10–15 hours or longer. If you’re bringing one to the beach, this may last the whole day. However, if you are bringing it on a camping trip, it may not last the whole trip.
In general, portable speakers are less about the connectivity and more about the target user. Some are good only for use on the patio, while others could be brought along on long camping trips.