Interesting about the purslane bbq. It really does seem to have a lot more omega-3, approximately 3 times more than spinach. So you wouldn't need to eat bushels of it if you want a similar ratio of omega6/3 as you would be getting with two tbsp of flax seeds.
I've never tasted it. Taste good, raw or cooked? Comparable to any other foods? Can you eat 10 ounces of it during the day with relish? I would be interested in growing it.