I would have to disagree with you. That is really a pretty black and white statement. Primarily because we really have not SEEN much from spyderco in the 300 to 400 dollar range. And if you mean to compare knives like the Slysz bowie (often compared to Sebenzas), and the Nirvana if you are willing to jump up to $450 to ZT knives of equal pricing? I'd say it isn't a completely fair comparison. When it comes to fit and finish, spyderco has ZT beat in that price range. That is however, not to say that ZT is significantly worse, because they are not. However I am going to cite the Slysz bowie as a prime example of the quality the Taichung factory can put out. ZT on the other hand, seems to mainly put out limited run knives come that price bracket. Their fit and finish is superb, but I have not found any examples which would allow one to say they are outright BETTER than spyderco in that price range.
When it comes to fit and finish, they are both extremely close. However, both companies have very different goals. ZT makes tough, militaristic style folders which you can hammer through a copper pipe. Spyderco makes ergonomic slicers. They are built to different purpose, however their fit and finish are both superb. I do need to point once more to the Slysz bowie as an ideal example of the midtech level of quality being put out by Taichung.