We opted for flush mount and a little bit "proud" (i.e. coming forward slightly from the bullnose). We brought it forward just far enough for the granite and the sink to meet at right angles without interference from the curve of the apron. Our granite goes in next week so I have no pictures to post of my own kitchen, but here are a couple of examples that I had found on line.

The corners on our sink are a bit more rounded than what you see in these two photos (which could possibly belong to someone on GW!), so ours probably comes out slightly further from the bullnose edge. I think undermount is more functional but I personally found the aesthetics of the flush mount to be the best choice for our space: