Ken and John both say 6 of 1 and half a dozen of the other. Both saws run real well. If both saws are built to equivalent specs., then the 066 should win because of its bigger displacement. Ken believes the difference to be maybe half a second in a 6 second cut. The 385 does responds very well to modifications, Ken indicating better than a 50% reduction in cutting times. The 066 is really strong out of the box and requires less work to bring it up to full woods potential.
So it all really comes down to which saw feels better rather than how fast they cut. On any given day, sprocket, bar, state of adjustment or chain could really level the playing field out in the woods.
Ken came up with a good recommendation and that was to get both saws, have them modified, see which one I like better, then sell the other one. I think that's what I'll probably do. It shouldn't be too hard to sell either KD saw to someone in the know. I'll get the 385/2186 from Dennis and the 066 from John (if I can figure a way to keep him from doing the JDHotsaw mods to it before sending it to Ken).