I started carrying a multitool in probably 2010-2011, beginning with some Chinese Leatherman knockoff I got as a Cub Scout. Since then I've used options from Gerber, Leatherman, and Victorinox. Over the years my selection has gradually shrunk in size due to competing pocket real estate between other gear, and a general preference to streamline things. None of these are defensive tools for me, just literal tools, which drives some of my selection. My background is office work for the last 10 years, but prior to that I was doing cleanouts, rehabs, and other blue collar work in the real estate sector.
For several years I carried a Leatherman Squirt PS4. That's probably the smallest I've gone, but it really punched above its weight class. About the only complaint I had with it was a lack of tweezers to deal with splinters and metal shavings, which were a surprisingly common issue for a couple years.
Never having used a Swiss Army Knife, I decided to try the Victorinox Tinker a couple years ago. There's definitely some trade-offs between the SAK style and a Leatherman style of tool, specifically the loss of pliers/scissors from the Squirt PS4. That said, I did gain some more effective drivers, and the tool itself is very well made. Between the two, I've had a hard time deciding which is "best" for me, though the Squirt PS4 is a go-to for gifts.
For larger tools, I keep a Leatherman Supertool 300 in my range bag, which has proven to be incredibly helpful both on and off the range. It's certainly something I could throw on a belt pouch, but that's not a concession I'm willing to make at this point in my life. The tools here are extremely high quality, and it's given me no cause for concern for nearly a decade of use.