Overall, for personal use, I prefer the Native. I'm both left handed, so it has an advantage there. Furthermore, I'm highly prejudiced in favor of front locks, will always choose one of them over something with any other lock.
Regarding the CF, I'll take the stuff on the Stretch II over either of them.
I would rate build quality as extremely similar, with that of the Sage being slightly higher if anything. Never been totally happy with the crisp corner the Japanese makers leave on the inside edge of liners. Those on the Sage are just rounded enough not to feel sharp if you drag your finger along them. Sage CF looks a bit prettier, the texture acts like facets to reflect more light, nice for dress use, but would probably not go over big with covert operators.
Sage is defintely heavier and thicker, so in that sense it would be the beefier of the two. Blades are very close to the same thickness and length but the Sage handle is a bit longer. Then again, the Native has the added weight of the lockbar, spring and backspacer, while the Sage has a wide open back, so am not really sure where the weight comes from. Thickness is easier to account for, the Sage has thick washers while the Native has either ultra thin ones, or none plus its CF is about twice as thick. That last is probably the reason it weighs more.
As Tony said, country of origin is a major factor in the price difference. Imagine that the lock is also a factor, front locks are more complex, requiring both more parts and more fussy work than liner locks. Probably the reason few custom makers offer them.
Paul
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