The Tenacious has a cheaper steel than the ZT 0350 but they're the same size.
The ZT looks and feels bigger.
The Tenacious has a larger cutting edge.
The ZT could probably handle more than the Tenacious, but it should with the increase in price and since it's made for heavy use.
The ZT feels good in the hand even if you have large hands though the handle can seem a little short.
The Liner lock is thick and strong.
Slices like crazy so it can handle the tough and lighter jobs.
ZT 0200:
It is very similar in size to the Recon 1.
Even though the Recon 1 is a beefy blade the ZT is much beefier and hefty.
The Recon 1 has a slightly longer blade and closed length so it's longer.
The steel is much better and the blade is thicker than on the Recon 1.
ZT 0350 vs. ZT 0200:
ZT 0200 - Much larger and beefier
ZT 0350 - While smaller, still a tank.
ZT 0200 - 154CM steel, a good steel.
ZT 0350 - s30v steel, very nice steel and slightly better than 154CM when it comes to certain things.
ZT 0200 - Thicker and you feel it more in the pocket.
ZT 0350 - A tank with a thick lock and blade but still rides in the pocket easier than the 0200.
ZT 0200 - Large blade with a lot of edge.
ZT 0350 - Still a good sized blade with enough edge for most EDC and work tasks.
ZT 0200 - Non-assisted flipper - while the blade is large and the heft helps deploy the blade well, it can be a sometimes slow movement because of said heft.
ZT 0350 - Assisted opening - quick even though it's a hefty little blade. You can even remove the torsion bar and it makes a great manual flipper.
ZT 0200 - A large beefy handle with awesome machined G-10 for an excellent grip that fits the hand very well.
ZT 0350 - Feels good in the hand, not too thick or wide, though the handle could be a little longer for XL hands.
Really it just depends on what works for you best.