Namco's first party peripherials for its Time Crisis series are typically fantastic. The new Guncon 3 looks to be no exception. It's apparently very accurate. How accurate? Way more accurate than the Wii-mote. Time Crisis 4 producer Teruaki Minami explains:
...Guncon 3's LED markers are actually much more accurate. Much better than Nintendo Wii's controller. In the Wii, there are only two LED points, but for the Guncon 3 there are six LED points, so it is more accurate than the Wii. The PlayStation 3 will be able to recognise the tilt of the Guncon 3, its distance from the monitor, and these things cannot be done with the Wii system.
What's more, the Guncon 3 also has SIXAXIS capabilities as well. It's also bright orange so some idiot doesn't use it to hold up a gas station.
Time Crisis 4 Interview [Gamasutra]