The servo control makes them settle very quickly anyway, but with three drivers (6 for both channels), the bass is extremely fast and articulate. If you've ever heard Magneplanars, particularly larger ones, the bass has a similar quality except the GR subs go considerably deeper and are a bit more dynamic.
The bass doesn't pressurize the room quite like a sealed box sub, since you are moving air from one part of the room to the other. So musical instruments sound more natural, but movie sound effects such as explosions don't have as much of a shock wave feel. If your primary use is home theater and you like movies with exploding helicopters, I'd probably stick with more conventional sealed box powered subs, but for music, the OB servo subs can't be beat.
I would expect the OB subs to integrate much easier with the OB speakers compared to a traditional sealed box sub. It's kind of the same issue with trying to integrate subs with Maggie's. But I haven't tried so I don't know for sure. I would post your question on AudioCircle in the GR Research forum to see if anyone else has experience.
I live in Portland, OR so quite a trek from Michigan.
It took me about 50 hours to build both the NX-Oticas and subs. Probably 30 for just the NX-Oticas. Most of that was painting. Building the cabinets was very easy - probably a couple hours total. The crossovers and wiring up the drivers took about 8 hours. And cutting and installing the NoRez for speakers and subs took another few hours.