800Z is more saturated Chazzy and more contrasty and has the fourth emulsion layer that improves it's performance in mixed lighting, whereas Kodak Portra 800 is softer in contrast, colour balance, and saturation that makes it particularly suitable for portraits in low lighting conditions. IMHO Fuji 800Z is much more suitable film for general purpose available light photography and capable of amazing results considering it's speed in low light.