Now for me, I carry a SAK. However, after that motorcycle accident a couple of years ago that shattered my shoulder, I greatly appreciate one hand opening. I could not use one of my arms to open a knife very easily for a long time. So, I bought a Spyderco UK Penknife to pair with my SAK. Best choice I ever made. It is not traditional, but it is a slip joint and it has better steel that most any slip joint. But the main thing is the safe one hand use. It can't accidentally close (use one and you will see why) and it is easy to stow away, again, after use.
I carry a SAK because I like to have tools with me when I need them. I need scissors, screw drivers, and something pokey that is not a knife all the time.
Like I said, for me, a perfect pairing.