My favorite multi-tool changes with my lifestyle. Long ago, I was happy with a Swisschamp as my only multi-tool, not even caring what else there was available. Apart from feeling the necessity of carrying a good quality m-t (why waste pocket space with something that has one blade only?), I had no interest in them as a subject, let alone a hobby.
That lasted for years until I encountered my first Leatherman, a PST. Instantly, I was pretty much won over with the concept of an actually usable pliers in the multi-implement mix. After a reasonable trial period, though, I returned to the SAK. It seemed to me that overall, I got more utility from the Swisschamp than the PST.
But that all changed when I discovered the original version Super Tool, with its locking implements and sturdy build. It was love at first sight, and the honeymoon lasted. The only thing missing was scissors, but then leatherman brought forth the Micra, which supplemented the ST perfectly. For the next 9 years, those two were my constant companions.
Somewhere on the journey, I got interested in multi-tools, even regular knives, and acquired several. I like to evaluate them in actual work, keeping the ones that suit me and selling off or giving away those that don't (I'm not a collector, never liked too much stuff in my life).
Today, I have about a dozen total Leathermen and Vic SAKs, selected for daily carry based on what kind of day I anticipate. If "serious" work is on the agenda, I take the ST 300, an improved version of the original I liked so much. For "out and about," I go with a Charge TTi because of its versatility, one hand blade opening and lighter weight. When I travel, it's with the 'champ because it's legal and non-controversial almost everywhere, and still provides a whole lot of capability. If I really don't want to be bothered, but as a once Boy Scout, (nobody is ever a
former Boy Scout

) I pocket an S2, and no matter what larger m-t I'm carrying, a Vic Rambler is always on board in my jeans watch pocket.
Whichever I'm carrying or using at a given time is my favorite.
