It's OK. Loud enough to cover a relatively big area (hotel pool-restaurant). The quality of the sound is much better than cheap no-name speakers. The anti-feedback button does absolutely nothing. One day, one of the speakers had a bit distorted sound. I couldn't specify the reason because of the infinite variables that could contribute to this.
In general it is OK, but I need to check them out in the long term, it' very early at the moment.