the only 'new' 6336s out there are in someone's inventory, I guess.
Scaled Instruments had one earlier this year, and admittedly the demand would be low.
One of the contributors here has a 5103 hooked up through one and at least a year or two ago loved it.
there was discussion as to the responsiveness of the propeller vs. cups, with the cups never having to orient into the wind, but the 5013 is a solid performer with a boatload of uses in marine, NOAA and other locations. Plus they are very neat to watch.