So what is the deal with arugula? I see it called for in so MANY recipes . . . often as a main ingredient (esp. in Cooking Light magazine) and I can't seem to ever find it in the stores here. Maybe once in awhile it appears as a green in part of a bagged salad, bleh. So . . . is there another leafy green that makes a good substitute? Does arugula really have that much to offer? I can't even remember what it tastes like, bitter? Peppery? Thanks for any input!