The Cortland is a popular baking apple, and I think I know why: it's big, so with a little peeling you get a lot of apple. It is a streaky red-and yellow apple of good size.
There's another good reason for the popularity of the Cortland apple, especially for caterers: it has a nice white inside and it doesn't turn brown like other apples do, so you can set it out on a cheese plate or a salad without misting it with lemon juice.
But in spite of all those cosmetic benefits, I prefer other apples for most every culinary use.