I'm in zone 8b.  I planted these in 4 40 ft rows about 2 weeks apart.  If harvested at the normal size they were excellent.  My wife wanted me to let them get larger but when I did they lost some taste and crispness.  So to satisfy my wife I ordered some larger varieties from Baker Creek for this fall.  We'll see how they turn out.  I would say they are a good all around radish.