Personally, I consider the JBL Flip 4 the best portable speaker. Apart from its 12 hours autonomy, it is waterproof and it has a wireless connection allowing two phones at once. Seriously, an excellent audio and quality.
For me as a fanatic audio listener, I have tried many other brands and the sound of those speakers are incredible. It has a great audio through its dual external passive radiators. Apart from that, all-weather companion features built-in noise and echo canceling for dual-use as a speakerphone, as well as JBL Connect+ technology that wirelessly links 100-plus JBL Connect+ enabled speakers for superior audio amplification.