I wonder how they compare to Danny's GR Research designs.
A Jeff Bagby design was very good for using off the shelf drivers, but that's with using off the shelf drivers. If going like for like inside parts quality, they're solid but certainly voiced different. Usually more in parts count, and less effecient though. My friend built out the Helios and I think they would play more against the X-LS than they would my NX-Studios. They are really nice and have bass for days with that side passive radiator, but they don't have the spacial cues or snappy attack quite the same. Definitely a fun speaker to rock out and get lost in the music to, and I mean that in all the positive ways, not an underhanded compliment. $/$ GR Research is a better buy on the higher end scale as far as sound quality per $ spent in my opinion, even if most of Danny's monitors require a sub.