I was using 7.3.2 for a few months on Vista and now currently on windows 7 for a week with no problems.  The only slim devices I have are the duet controller and receiver.   

I decided to give squeezecenter 7.4 build 26597 a shot.  It installed ok, the controller upgraded its firmware and reset.  The problem was the squeezecenter had a message in the playlist area that said something like press the brightness button to upgrade firmware on player.  Well, the duet doesn't have a brightness button.  On the controller I was able to browse my library and "play' songs and the controller acted like they were playing but no sound.  I tried doing a factory reset on the remote, unplugging the receiver and one time I saw a message on controller that it was updating firmware on receiver but it was stuck there for a while (20+ minutes).  I eventually reset the controller.  The receiver firmware displayed on squeezecenter and controller was version 58.

I then tried to install a latter build, 26644, but it had the same issue and I didn't see the receiver firmware upgrade message on the controller again.  I un-installed this and went back to version 7.3.2 and it worked with no problems (firmware on controller and receiver reverted back no problem).  I then installed 7.3.3 build 26557 and it worked fine and the receiver firmware upgraded to 60 with no problems.  I was able to play music fine.  

I decided to give 7.4 another go so I installed the latest build, 26650, and it now works fine (receiver firmware still at version 60, is this correct?).  I've been using for a few hours now.