Bluetooth and AirPlay essentially do the same thing: transmit audio wirelessly. How they go about it, though, is quite different. Bluetooth is a short-range, low-power transmission. This is great for portable devices, easy connectivity, and long battery life. However, in most implementations, it's not able to transmit the same amount of data as AirPlay. Meaning? Worse sound quality. "Bluetooth compresses the data, which compromises the audio," says audio expert Brent Butterworth. "You may not notice this with very compact systems, but with better equipment, it's quite noticeable." AirPlay uses a WiFi connection, which allows bit-for-bit identical transmission of all digital tracks. In other words, your music will sound more like it did in its initial recording and less like a reduced version of itself. Here are five systems we like best.