I actually really love kale-  have you ever had it?
I love it! It's so good for you.  I like both the green and purple varieties. 
I've never seen purple kale - is it the same?
Yes, both the green and purple kinds have similar leaves. 
Is the purple as nutritious as the green?
Kale
Kale () or leaf cabbage is one of certain cultivars of cabbage ("Brassica oleracea") grown for their edible leaves, although some are used as ornamentals. Kale plants have green or purple leaves, and the central leaves do not form a head (as with headed cabbage). Kales are considered to be closer to wild cabbage than most of the many domesticated forms of "Brassica oleracea".
Etymology.
"Kale" originates from Northern Middle English "cale" (compare Scots "kail
with deep purple or burgundy tints on the lower stems, and a scallion-like stalk and bulb. Both the white lower leaf stalks and the broad green leaves are edible. The flower stalk appears after the leaves have died back, unlike the similar "Allium ursinum", in which leaves and flowers can be seen at the same time. Ramps grow in close groups strongly rooted just beneath the surface of the soil.
Taxonomy.
"Allium tricoccum" was first named as such in 1789 by the Scottish botanist