The plain old Wenger SI has been my sole EDC for a lot of times past. But for the last several years, it has been paired with the little classic on my keyring. BUT...I started out my knife life with a standard Camillus scout knife dad gave me at age 12. that knife served me as a sole EDC from age 12 to 19, when I enlisted in the army. There I got a issue a Camillus 808, the 'demo' knife. I used that army issue scout knife from age 20 to about 25. Then While stationed in Germany, I bought a few SAK's at a knife shop. My very first SAK's. A huntsman, and the Wenger SI. Eventually the huntsman was too bulky in the pocket so the Wenger SI became my EDC for many years. Later I tried a tinker, a recruit, and a few others. They all came and went, mostly went. Spoiled by the metal handles of the Camillus demo and the Wenger Si, I never really was confident int he plastic scales.
Then I got a Victorinox pioneer as a gift, and I carried that as a sole EDC many times over the years. Many times it was paired up withy old Buck 301 stockman, but sometimes it was alone. There's been other knives of course being a knife nut, but I think I was spoiled very early on in life by the scout knife pattern. Having a few basic tools on my pocket knife of the day had become a habit, and eventually all the other knives faded out as I got older and backed away from the whole knife obsession thing. To me the Wenger SI/Victorinox pioneer, and Camillus demo knife is the perfect pocket for modern life. It can do anything a knife is needed for like opening packages, cutting cordage, dealing with food on camping trips, gut pan fish if a dedicated fishing knife is not available. BUT...it deals with flat and Phillips screws, make starter holes for wood screws, open bottle and cans, the can opener makes a great staple remover, the bottle opener tool makes great pry tool for paint and putty cans, can strip wire for electric repairs, make a hole in a belt for loosing weight, and much else.
I lost my taste for dedicated pocket knives long ago. it became my way of thinking that a pocket knife, with just blades, is a shallow one trick pony with little real world mission capability. A SAK, no matter if a pioneer, cadet, tinker, whatever, is a great sole EDC because it's not just a knife. Even a simple scout knife is a small bundle of solutions for some of the everyday problems that a mere knife can't deal with. Now I am on my second Wenger SI as my old one was pretty worn out by 35-40 years of service. I love the basic SI/pioneer pattern as my favorite and most carried SAK over the years since that day in 1969, when I got my first one.