I have stuck with the DN-60 even though it is temperamental to say the least.
Yesterday I was recording interviews and the DN-60 went out of Sync. This is solvable with interviews but impossible to solve with dances. Unless someone has a solution back to tape only for the dances.
I use SanDisk 32GB Extreme 60MB/s.

I have heard of this happening, I believe that playing the video via the firewire into the PC brings the sound back in sync.
I take mainly dance competition video and have had no problems with the sound being out of sync.

Regards,

Martin