Best Purple Basil

Could you please tell me which is the best color retentive purple basil to grow as an ornamental.

The classic purple variety, the 1960 All-America winner 'Dark Opal', has fallen from its former glory. The variety has not been maintained. Formerly, careful seed growers took pains to rogue out plants that reverted to green. Now it seems that seed growers are doing nothing to stop the regression to green and each year the variety deteriorates further.
In the late eighties, another All-America winner was introduced, 'Purple Ruffles'. It had lovely almost black, dark purple curled leaves. But it too deteriorated, becoming over 20% green by the early nineties. Again, lack of attention by the seed growers is responsible for the deterioration. In 1993, Richters introduced the first new purple variety to replace 'Dark Opal', the European-bred cultivar 'Rubin' basil. This variety is not as dark as the original 'Dark Opal' or 'Purple Ruffles', but it has proved to be a reliable replacement. The edges of some leaves fade slightly towards green in low light, but it is a major improvement over the other varieties.