"Native and the Native 3? Delica and the delica 3? Calypso, jr., and the 3."
The Calypso 3 is G-10 with SS liner and is quite solid. The Calypso Jr. is very light and has FRN scales with no liners. The Delica 3 is like the Calypso Jr. FRN, light, no liners. The Delica 4 is the newest one. It is heavier, less pointy, has nested liners and is a solid knife.
I really don't think the Delica 4 is any better or worse than the Delica 3. I prefer the D-3 since I think the pointy tip is more useful and the light weight makes it easy to carry. I really like both Calypsos but they are very different from each other. More different than the Delicas I think. The D-4 is just an upgraded D-3 but the Calypso 3 is a compleatly different idea than the Calypso JR. You really have to handle them to see what I mean.
I am not a fan of the Native at all. It is all wrong for me. There are many people that think it is one of the best Spydercos for the money. I don't like the handle, the blade grind or the overall feel. If I were to get a knife in that price range, I would go with the Centofante 4 or even the Delica 4.
All that being said, the Calypso 3 is a heck of knife and it is by far and anyway my favorite out of the small 3" folders. It is a class act that you will not think is over priced once you get it in your hands. I would rather have one Calypso 3 than two Natives or two Delicas. It is that good. You should be able to get them for $80-90 if you look around. Maybe less if you find someone selling one in the want ads.