#1 Based on what you will be doing
Choose a buoyancy aid for SUP up to 2 miles from land (3.22 km).
For recreational use, a foam vest will be easier to use and will provide buoyancy immediately if you fall in the water.
If you want one that takes up less space, choose a manual inflatable PFD with a gas cartridge, which will leave your shoulders free to move. Please note, you must pull on the handle to inflate the buoyancy aid as needed. Some buoyancy aids also feature a hydration bladder pocket at the back so you can easily stay hydrated as you paddle.