S7=good for gig tough knives
SR101= good for little knives with great edge retention but can be tough when diff tempered
INFI= good at both.

For most types of knives you only need either a lot of toughness like for a survival knife or excellent edge holding for a hunting or wood carving knife.
If you want your survival knife to hold an edge like a D2 hunter and cost is no object then INFI is a good choice. Or if you want a hunting knife you can pry a car trunk open with INFI is also good. But if all you need is a really good hunting knife (and you are not worried about rust)SR101/52100 is a great one.

If you want the worlds toughest production survival knife then you want a S7 Scrapper.