I would say Lane 1's discontinued BlueBerry Buzzsaw...
It is a very even rolling ball, and even left in the stock highly polished coverstock, the Brunswick Powercoil coverstock can read just about any lane condition very well. Also if you the coverstock is probably the most adjustable coverstock on the market, sanded it reacts like a partical, polished and it acts more like a resin, but with out an excessive over-under.
The core is the Lane 1 diamond, but with the dual mini nuggets, it gets an increabile midlane read. It is a smooth rolling ball, with a hard but controllable arc in the back of the midlane.
You can play any lane with this ball, if you are willing to adjust, the readablity of this ball is incredible.
Lane 1 released the Cranberry Buzzsaw, with a longer read, and a snappy back end, but this ball will not read oil nearly as well as the BlueBerry.
If you can pick one up, I would highly recommend it.