How do the DoubleTree models compare to the regular models? In particular, I am considering the Copperliner model; Boker makes it in either stag or jigged bone with minimal etching or in a DoubleTree model with heavier etching and fancy bolsters. I like both, but is there any difference in type of steel used for the blade or fit and finish? Any quality issues with either? I like the traditional slipjoint appearance and size, but with the convenience of a liner lock on both of these models. Any thoughts would be most helpful. Thank you.