All of the literature calls this rose a ground cover plant, but mine passed the 12-foot mark long ago. It's extraordinarily resistant to pests and diseases and is quite easy to grow.
How would you compare it to Ballerina, Zuzu? In my experience Ballerina always loses its leaves from blackspot in its first year and I've never had Ballerina repeat; but I absolutely love the way Ballerina spaces its small blossoms over the outside of the plant.
There really isn't much basis for comparison. They're both wonderful, but 'Ballerina' is a nice compact plant that can take a little shade in my garden and 'Smarty' is a monster that grows best in full sun and demands either an arbor for support or constant pruning to keep it within bounds. My 'Ballerina' reblooms as often as 'Smarty' does. 'Smarty' might be a little more disease resistant than 'Ballerina.'
Thanks. Very helpful. The photos of the individual flowers seem similar to me. Single. Lots of them. Nearly white. I guess choosing roses solely on the basis of the flowers we see in photos is a little like choosing a spouse solely on the basis of a photo. What matters more is the stuff you don't see in the well-posed shot.