Depends on what you're priorities are.
Native IV has the prettiest CF, and that deep choil provides a lot of security. Its other plus for me is the absence of a Boye dent.
Caly 3 offers ZDP, albeit with easily scratched outer layers of 420J2. Pluses would be that it's the most compact of the three, and carries the most discreetly due to the lowrider wire clip. It also has the thinnest grind behind the edge, so it's the best slicer. Negatives, for me anyway, would be lack of TD carry option, lack of a lanyard hole, and smooth matte CF that's neither grippy nor particularly attractive.
Stretch offers solid ZDP blade, an extra half inch of blade length, and the combination of an naturally secure handle and peel ply CF. Blade is a bit thicker behind the edge than the Caly 3, but it's still a damn good slicer. Downside, for some is that the peel ply texture makes the CF pattern so subtle they feel it's not enough different looking from G-10 to be worth the up-charge. To its credit though, the texture on peel ply CF outlasts that on G-10. I'll freely admit to being prejudiced here but, IMHO, the Stretch is simply the best EDC folder Spyderco has ever built.
Paul
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