I grow Evening Enchantment, and I love it. It holds it's color beautifully, even when our temps hit 100. I live in SC, zone 8b. Another reason that I like it...it has a great green throat; it's so green that it is hard to sometimes get a good picture because my iPad can't focus on the green and the purple at the same time. It does not fade or slick here, but it does get some very late afternoon/evening shade.
First flower open was May 20th. It rebloomed here, so it continued flowering well into July. I've had it for two summers, and it has formed a nice clump.
These pics don't do it justice:)
I purchased mine from a local grower, Charles Shaw (Shaw's Sunshine Gardens) in Augusta, Georgia for $10.