This has been an interesting thread. While I have not owned a Sage II, I have or have had other Taiwan made Spdyercos. I was suprised at the quality & honestly, have been disappointed by "some" of the Spydercos coming out of Japan.
Also, I believe Sal himself has said that he uses the particular Taiwain factory because of the quality knives it puts out, not the cost. In fact, IIRC, he said there isn't really a savings using them (When using higher end materials) because of the increase of shipping costs (Shipping S30V to Taiwan, then the product back to the U.S., along with customs costs, etc).
Now, having said that, what surprises me, to my delight, is Spyderco's ability to produce the Manix 2 at the msrp (& street price) that it's at AND being made in the U.S. I just can not believe that 154CM is THAT much cheaper than S30V. However, I'm glad they made it & at that price point.
The Sage II vs Sebenza has also been interesting. I'm sure it's a very nice knife, but I believe someone wrote the comment that the Sebenza feels like it's more "heftier" than the Sage II & the Sage II feels "lighter" in the hand. That's interesting since I believe the Sage II's specs lists it as being heavier than the Sebenza. My guess, it the poster meant that the Sebenza felt more solid, maybe? Again, I have not owned a Sage II, so I can't comment on it. I do & have owned quite a few Sebs (6, I believe) along with other Ti frame-locks that I've read many member comment about in comparison to the Seb (BM Skirmish & Bradley Alias come to mind), but IMHO, I believe the Seb is superior to the others.
Again, I can't comment on the Sage II. I will say that I have came across a folder that I feel is the equal to or possibly a little better than the small Seb, but it's a custom.