slow1,
Beginning with the blade, the Calypso's 4 inch blade is a flat grind VG-10, whereas the Endura's blade is just under 4 inches and is ATS55. In terms of blade shape the Endura has more of a distinct hump at the Spyderhole. As for the handles, the Calypso is micarta, and the Endura is zytel. The Endura has a reversible clip; the Calypso does not.
Even though some refer to the Calypso as a "dress up" Endura, there are a lot of differences in these two knives. I personally like the Calypso better because of its superior steel and the slick look of the micarta. Even though the clip is not reversible on the Calypso, the clip is placed so that the knife rides remarkably low in the pocket.
------------------
Guyon
AKTI Member #A001044
"The hardest knife ill used doth lose his edge."
-William Shakespeare, Sonnet 95