traktor scratch runs without problems on windows 7 RC.
i installed traktor scratch version 1.3.1050 today without problems.
the recent USB driver from the NI website for audio 8 DJ interface also works. after the driver installation the USB interface was not detected and was still listed as “unknown device” within device manager – right click on unknown device and click add driver… locate the driver manually on your harddisk (browse… – normal install path is C:\Program Files\Native Instruments\Audio 8 DJ Driver).
NI service center software also runs without problems.
after playing for about 4 hours i got the impression it runs smoother on windows 7 RC than vista.