Hi, I'v heard both speakers. To me the JM Lab Mezzo Utopias are better. I heard them on an unbelievable system, Krell Amps, Pass O1 preamp, Jadis JS 1 tube dac, with a separate tube power supply. There are like 4 tubes in the Jadis power supply, along with 2 tubes in the dac. Jadis JD 1 transport, MIT 850 speaker cables and MIT interconnects. The JM Lab sounded so articulate. The bass was fast and tight. What I really liked about these speakers was the crossover, the bass blended in so perfectly with the midbase driver. The midrange on these speakers is top notch. That Jadis dac is unbelievable sounding to. I heard the BW Nautilus 802 on an all Proceed system, Proceed 250 watt amp, Proceed preamp processor, Proceed CD Player. The Nautilus 802s have a nice articulate sound to. I just felt they lacked alittle bass. The bass response on the JM Lab Mezzo Utopias was so much better then the Nautilus 802s. I heard the Montana XP speakers. Personally, I dont like that Scanspeak Kelvar Midbase driver they use. The Montana's just sounded to edgy. I emailed the designer of Montana and told him to use the new Scanspeak 5 inch Revelator midbase drivers. Those drivers are light years better then the Scanspeak Kelvar drivers. The Kelvar midbase on the Nautilus speakers sounds really good. It has a warm articulate sound. I just think the Nautilus 802s lack bass.