Buy the Soundcore Boom Go 3i Portable Bluetooth Speaker.

It plays longer, hits harder, and survives worse accidents than the JBL Go 4, and that is what actually matters once you take it out the door.

What was compared

1. All day battery, no top-up panic
The Boom Go 3i runs 24 hours on a charge against the JBL Go 4's 7, so a full day at the beach or a weekend camping trip never dies on you. The Go 4 needs a recharge before dinner, the Boom Go 3i does not.
2. Fills a yard, not just a nightstand
15W from two drivers pushes real volume and bass the JBL Go 4's single small driver cannot match outdoors, over wind or a crowd. Push both past half volume and the Go 4 thins out fast while the Boom Go 3i stays full.
3. Survives an actual dunk, not just a splash
IP68 means the Boom Go 3i shrugs off full submersion, while the JBL Go 4's IP67 rating only covers dust and brief splashes. Drop either one in the pool by accident and the Go 4 is the one you are gambling with.
4. Doubles as a backup charger when you need one
Emergency charging output and app-based BassUp EQ tuning give the Boom Go 3i real extra utility the Go 4 simply does not offer. If your phone dies on a hike, the Boom Go 3i can help bail you out, the Go 4 cannot.
5. Yes, it costs $30 more. Here's why.
The Go 4 is $30 cheaper and smaller, fine if you only want a shower speaker or a keychain clip-on, and that is a real buyer. For anyone who wants a speaker that lasts all day and actually fills a room, the extra cost buys real use, not spec padding.