First of all, the drive-line. Now that I have the gear greasing figured out, it's pretty much transparent. I just don't notice it. I can ride 500-600 km between shots of grease, and this is not an issue for me. In fact, it's a big advantage. I really don't miss chain maintenance. At all. (If you read Jeff's site, you'll find he's greasing every 75 mi or so, which to me seems way too often.)
My main drive-line complaint comes intermittently on hot days when I get a "tunk" sound once per pedal revolution when my left crank is straight up and down. Faster cadences make it louder than slow. Light pressure and very hard pressure make it go away, and if the temperature is below 90°F, I don't hear it. It's always over 90°F in the summer in Austin, and I only get about half the time. Although it's only a minor annoyance, I wish I knew what it was.
Build quality. It's a little late for me to talk about build quality since I already mentioned the state of the wheels on receipt, but I did purchase a Park TM-1 spoke tension meter and tuned up the wheels. This is a necessary item of maintenance anyway, and I probably should have done it 2000km ago, but it feels like a new ride now, and I'll make this a regular date with the bike in the future. Regarding build quality, everything else is holding up well, and no other defects have come to light.
One last unspoken complaint relates to getting the driveline. This may seem a little obscure to all but the few Dynamic-owner readers that I have here, so feel free to skip on by if you want. Early in my setup, I was having trouble with grinding gears that turned out to be a problem of sorting out the proper kind of grease to use. During the process, though, I found I could make a big improvement to the feel of the drive line by adjusting the number of spacers on the rear axle. These are thin shim-stock washers that go between the hub and the drop-out to properly align the bevel gear with the drive shaft. The bike came with three fitted, and I improved the feel of the drive line noticeably by removing two of them. Later, the teflon-based grease solved the rest of the grinding problem, but I recently put them back in, just for kicks, to see what would happen, and I had to pull over and take them back off because the drive train became rough and the friction increased. I'm guessing that my gear set has probably worn in to its current arrangement and that putting them back in a long time ago wouldn't have had the same effect. Again, this is minor, and probably only of note to anyone else searching the net for information on shaft drives.
So I set out to try to complain a little bit about my bike, but I've ended up dismissing all of my complaints as minor. The fact remains, I like the bike, and I don't (honestly now) regret choosing it over a more conventional one, even after 4000km through Texas heat.