I use this with acoustic guitar and mic for song. Primary use are very small cafe's, occasional street music, and a mini-rig for demo-ing myself to new customers.
It's fairly low weight and ergonomics makes it easy to handle, and setup time is extremely fast as mixer is onboard - just plug in, and go (after initial playing around and getting the sound and volume right)
This is a very nice sounding box and with only just a little eq'ing everything sounds very good and pleasantly natural.
I also like that it charges the battery - or operates directly from - the quipped 220v IEC mains connector - and that you can power you ipad or pedals from the built-in usb ports (although if you have the box on a stand as I usually do, it will be some nasty long charger cables... better to have a seperate powerbank ;) )
Although I really like this box, there are some drawbacks. Firstly, In order to turn effects on and off, you need the app - not really a problem, but sometimes having a footswitch is just more convenient.
The sound level is OK - but I find myself driving it at max volume to get a decent sound level, i.e. it just blinks red occasionally indicating clipping starts. Clipping is not digital or analogue distortion, but the jbl it starts compressing the sthe sound more and more noticably the more it "clips" - so you are not hurting anyones ears, it just becomes... well, squashed. I miss a some headroom here, as I find when driving speakers they tend to loose "control" over the sound.
Bottom line is that this speaker without competition for its price. This speaker sounds awesome for my guitar and vocal, but I wish it was just a tad louder.