Reviews have been published for the JBL Xtreme 4 and JBL Xtreme 5 Bluetooth speakers. The Xtreme 5 is described as an upgrade with improved bass, clarity, and power, with some outlets considering it worth the price. However, it is unclear how the Xtreme 4 and Xtreme 5 compare in terms of overall quality, as both have received positive reviews, with the Xtreme 4 being called a "5-star winner" and the Xtreme 5 being praised for its audio.