You can't go wrong either way!
Exactly. Just depends on how big and heavy a knife you like to carry. Here are the specs of both knives:
ZT 0801:
• Made in the USA
• Manual open, KVT ball-bearing system
• Frame lock
• Reversible (left/right), deep-carry clip
• Steel: ELMAX®, stonewashed finish
• Handle: Titanium
• Blade Length: 3.5 in. (8.9 cm)
• Closed Length: 4.7 in. (11.9 cm)
• Overall Length: 8.2 in. (20.8 cm)
• Weight: 5.8 oz. (164.4 g)
ZT 0770CF:
• Made in the USA
• Assisted opening
• Inset liner lock
• Reversible deep-carry clip (left/right)
• Steel: ELMAX®, stonewashed finish
• Handle: Carbon fiber
• Blade Length: 3.25 in. (8.3 cm)
• Closed Length: 4.3 in. (10.9 in.)
• Overall Length: 7.5 in. (19.2 cm)
• Weight: 3 oz. (85 g)
I only carry lightweight folders, so the 0770CF would be my choice.