I just had the opportunity to A/B compare the Genz Benz 410 XB2 and 610 XB2 powered by my trusty Ampeg SVT-3PRO, and thought it might be helpful to share my impressions. I tried the 410 first. I've been using this amp with a Euphonic Audio VL210, which is 8 ohms, so I can't get more than about 275W out of the amp. The 410 is 4 ohms, so I get more like 450W, and it has twice as much driver area, and seems much more efficient. There was a lot more low end, especially farther away from it (the VL210 is like an earthquake for about 6 feet, beyond that the bottom octave just kind of dissipates). My fretless sounded great, and the Rick was awesome, I don't think it's ever sounded that good. In comparison, the 610 had even more deep low end, and was more solid throughout the bass and midrange. I could only get about one wavelength of low E away from it (a 25 foot guitar cord) so it's probably not surprising that the low end became relatively more prominent at this distance. I left the horn attenuator set halfway (straight up) on both cabinets. They both sounded about the same in the high range (probably because it's the same horn). Other than the amazing low end low end of the 610, both of these cabinets have a substantially similar character. I like to play hard and saturate the tube preamp, and both of them did a good job of bringing this out with a percussive, crunchy attack and thick, solid sustain. If sound alone had been the only consideration, I would have bought the 610. The low end is truly amazing - I think in a lot of clubs you'd have to mike even a loud drummer to keep up with this thing (given the power it can handle). But the 610 weighs 50% more and would have cost over 50% more, and my Ampeg doesn't have enough power to really drive it enough to get 50% more of what I want. So I bought the 410. BTW, if you're in the Seattle area, the 610 is still on sale at a pretty good price at Bellevue American Music, and I think Johnny might even be willing to deal a little. If you have a kilowatt or so to drive it and you're looking for a speaker, it's worth checking it out.