Don't drink the cool-aid just yet, I've owned a couple of these. The weatherproofing of the unit is almost non-existent. It'll survive some sprinkles sure, but light immersion or serious water exposure and the speakers on it will fail.
The sound is usually pretty damn good for what it is, i'll say that but it lacks bass and some mid-range. Software dependency for expanded operation is very dodgy at best in terms of functionality.
If you can get one for about 75-90 bucks, it's a good enough deal for something to take with you when you travel. I've strapped on one or two these to a motorcycle and paired it to my streaming device for beats on the go. Battery performance before the unit starts to fail can get you about 3-4 days of streaming audio at 4-6 hour intervals.
I have JBL Flip 4, recently purchased from flipkart, now the issue is with charging. It is not taking charging with original JBL cable, I call on JBL customer care number at 1800-102-0525, they advised me to visit the nearest JBL service center at my location. After visiting the service center, they said JBL doesn't provide warranty of accessories. But third party cable can damage the port.
TheJBL Flip 4 and Flip 5, it kinda depends on what you need. The Flip 5 usually sounds a bit better and has longer battery life, but the Flip 4 might be cheaper and has a built-in mic for calls. If you're into waterproofing, both are good, but Flip 5's got a bit more durability. Check out this link for more details: https://hifiaudios.com/speakers/jbl-flip-4-vs-flip-5/