Well, I was hoping you would get some responses by now. We also have 2 islands and love the design. Like yours, one is a prep island, and the other a saving/buffet island. They are not exactly the same size....the buffet island is a barrier between the kitchen and the great room. It is a bit smaller than the prep island. They line up on one side, but not on the other. Also, the prep island is a rectangle, but the serving island is curved on the outside, so they are different in appearances. It looks good this way and is cohesive.

Thanks for your answer ! I'd love to see your islands. Your situation sounds like mine. The serving island would be between the kitchen and great room/family room. Planning on converting that room to a dining/family area, farmhouse seating along fireplace. All these rooms tend to be on the long and narrow side.

Your situation is similiar also because only one side of the islands would line up. I read your response to my DH and he like your idea of curving the corners on the buffet island. I'll try putting that design on paper. Great, thanks again.

You could look on Houzz for double island kitchens. Here's a kitchen that has 2 very different, but lovely islands and a description of how they're used.

Here is a link that might be useful: bjwright1's kitchen w/ 2 islands