What are the differences, in terms of practical performance, of INFINI, SR101 and SR77? Are these differences very noticable?

Hmm, noone seems to have any thoughts on this. Is this impolite to ask, or is the answer painfully obvious (and something I'm missing)? If the topic's off-limits, I'll delete it.

I avoided this because I dont know the specifics, I've never owned all three or anything... From what I've heard for edge retention is something like INFI, sr101, sr77. For toughness is along the lines of sr77, infi, sr101. I would love if somebody corrected me on this. As for how noticable the differences are, I have no idea as like I said I've never had all three.

INFI good at everything but expensive.
SR101 also known as 52100 is good for edge retention and everything else just not quite so much as infi. I think it makes a great choice for smaller EDC blades.
Sr77 aka S7 is incredibly tough but not so good at other things ,it makes an incredible large knife or chopper.

The old saying was that most people would never take SR101 or INFI to the point where the differences in performance would be noticeable. INFI is pretty much a stainless steel as far as rust resistance goes, which is a big plus to many people. SR77 will not hold an edge quite as long as its sister steels, but is excellent for high impact abuse. Plus, with the Busse Heat treat, it will most likely outperform any other S7 on the market. Bottom line is: Good Stuff, All. <img src="/ubbthreads/images/graemlins/thumbup.gif" alt="" />

Hmmm, in my experience SR101 beats the hell out of SR77 in corrosion resistance. I haven't used my yard guard much at all, and while it hasn't developed any actual rust, it has developed a dark patina along the edge. I've used and abused my camp tramp quite a bit and it's still looking pretty good. <img src="/ubbthreads/images/graemlins/thumbup.gif" alt="" />
I've also rolled the edge on my guard pretty easily. after one somewhat heavy (at least as far as my skinny arms go) chop into a juniper branch and I could feel the edge had moved. My tramp, batac, and fbm had no such injuries after similar chops.

My understanding is that SR101 is slightly more stain resistant than SR77.

Either way, nothing a bit of preventative maintenace can't cure!

SR-77 is extremely tough. You can wail on it all day and you will break before it does. That being said, it does not hold an edge quite as well as INFI or SR101. Not saying that your SR77 knives won't stay sharp, believe me they will! SR101 and INFI will just hold it a little better.

For practical performance, you will have to decide what the balde is for. For the most part what will really affect the performance is what edge you decide to put on it. None of Dan's blades will disappoint you. Swamp Rat and Busse are the same way.

I don't have any SR101 - but - I haven't had any staining issues w/ my SR77 (or INFI).

I've found that the best way to keep an edge nice and shiny is to get out and use it frequently <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" />

Your experience sounds kinda strange (not saying I doubt it one bit) - I hope there isn't anything "wrong" with your blade!

I have had some very minor stains on my DF edge, using it did remove them though! <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" />

As others have stated, it's difficult to quantify "better". For instance, and this is simply what I've heard rather than from personal experience, SR77 will rust readily, but the corrosion remains a surface issue -- it doesn't pit. SR101 may actually resist corrosion a bit better, but I've heard that when it does rust, the corrosion penetrates, resulting in pitting. I've also read that INFI was not designed to be stainless, but in practice, it's very corrosion resistant (if I had to guess, it would be due to Nitrogen content, like Spyderco's H-1 or Boker's X15).

As to both toughness and edge retention, the steel has a lot to do with it, but the tempering process is actually the number 1 factor. You can enhance the performance of poor steel with good tempering (at least up to a point) or absolutely ruin a good steel blade with bad tempering. That, more than anything else in my opinion, is the the key to the Busse (family) knives success. They start with good steel, although some other knives are made of almost the same material, but they use a superior tempering process.