Experience indicates that the S3 may not get Key Lime Pie. Even if it does, the S3's version of Key Lime Pie will probably be a hybrid bastard that looks and feels more like Ice Cream Sandwhich than Key Lime Pie.

Also, the next Nexus (or nexuses, as rumored) is likely to arrive in October. Anybody with a GNex already has a good phone and can afford to wait a month or two.