Now I've got this thing together it seems like a solid rack, but assembling it took hours. I combined it with the 2 bike add-on which is where most of the pain arose. The issues were:
1. Putting the first bolts through to attach the add-on were impossible due to poor quality finishing. The holes to push the bolts through were burred and the whole add-on assembly wouldn't slide in as a result. I filed the burrs, and got the add-on to slide in, but then couldn't get the bolts through. More filing and I got three out of four bolts in. The remaining one wouldn't go, and I had to loosen the bolts on the add-on section to get everything to fit, before retightening (not mention of this in the instructions).
2. Mounting the arms for the add-on section were also difficult. One bolt again didn't slide through. I couldn't get in to file this section to resorted to belting the bolt with a hammer while being careful not to damage any of the aluminum arms.
3. I attached the adapter for a 20" wheel and again difficult because the plastic housing was meant to hold the nut in place while you entered a bolt from the other side. Except that it didn't fit. In the process of tightening and trying to make it fit, the bolt sheared. Fortunately I needed only one 20" wheel adapter and I had two, so I had enough bolts.
4. This thing is HEAVY. Getting it out to the car took some sweat.
All that said, the rack is solid once on the car. It took all four bikes (2 adult / 2 kids) and stayed solid without shaking for a 220 mile drive. It's the most solid/secure bike rack I've ever had. I was impressed by how quickly and easily the bikes come on and off. The only criticism in use is that I cannot figure out how to lower the bikes to access the trunk when the bikes are on - think it's a two person job and requires someone else to support the weight while you pull the lever.