I have 2. The second was much easier to put together.  I did assemble them myself using a standard folding ladder. The first took about 8 hours and the second about 5.
The holes on the upper female curved pieces seemed to make slipping the smaller piece in difficult so I used a rotary file to smooth the lips of the holes so everything went together easily.  I've had the first one about a year and don't see any degradation of the shell.