I like INFI in fixed blades because it responds so well to my preferred method of maintaining sharpness...Spyderco Sharpmaker.
Also, I'm not a strop guy, but I've found INFI to respond really well to my Knivesplus stropblock.
So primarily for me it's INFI maintainability.
Secondarily: Busse's CBT & Competition Finish-- there's NOTHING else like it on the market...see if you agree:
Icing on the cake: Handle texturing and design. I'm a texture snob...peel ply <anything> gives me the heebiejeebies. Whenever I hang a nail on peel ply, it give me the "fingernails on chalkboard" sensation that bothers some folks

. So I'm really sucked in by canvas micarta, Res-C, and the macro-textured G10. I find the patterns Busse machines into their handles especially handsome. Some of the patterns in texture and color when the different colored plies are revealed are really zen for me!

Here's a few of my favorite patterns, enjoy!