Had a chance to compare the AT-6666 and the M8900 side by side.
M8900 is way smaller as you can see from the pictures below.
There is a lot more board inside the AT-6666 and I do like the integrated AT-6666 rear panel heatsink. A lot of metal in there but it looks difficult to cool. More fins and a fan might be more useful but there have been no reports of excessive heat on these recent models.
href=”https://dd182003.files.wordpress.com/2014/07/comparitive-size.jpg”> Side by Side M8900 on Right. The M8900 is a lot shorter than any 10/11m SSB Radio we have ever seen previously.[/caption]