As you may have seen on my flashlight post... I guess I'm pretty redundant.
The same follows with multi-tools:
I carry three pocket tools because each does something the other does not:
I have a Sheffield Multi-tool (Pliers-type; Leatherman Micra/Juice/Squirt size), Wenger SAK "Clippers," and Victorinox Hiker (Tinker + a small saw)
Sheffield - Has the following tools: pliers, scissors, flat head, phillips head, can/bottle opener, another flat head, awl, file (teeth all the way to the edge), blade
- I only use the pliers. All of the other tools are too difficult to access and use comfortably. It's either too hard to hold the tool or too hard to access what I need to manipulate. The Squirt is much more intuitively designed where the non-plier tools can be accessed and utilized easily. There is a locking clasp that just gets in the way of everything.
"Clippers" - Has the following tools: Nail clippers, scissors, blade, nail file, blade, tweezers, toothpick
- I use the nail clippers/file all the time and the scissors, which are much more usable than the scissors on the pliers tool.
Hiker - Has the following tools: Main blade, smaller blade, small saw, bottle opener/wide flat head, can opener/narrow flat head, awl, phillips head (orthogonal to the handle)
- I use the main blade, the saw, the bottle opener, and the phillips head
I got this for the larger blade (bigger and much more usable than the other two blades I was carrying) and for the phillips head screwdriver. I wasn't sure what other tools I would use... but I pretty regularly use the tweezers, saw, and bottle opener as well. I don't use the can opener because I also carry a P-38 can opener in my wallet which works much better.
In summary, if I had a tool with the following, I would be incredibly happy if I had the following in one single tool:
Pliers, large blade, phillips head screw driver (orthogonal to the handle), bottle opener, scissors, nail clippers, file.
The nail clippers are perhaps a niche item, but they're incredibly useful beyond just clipping nails. Outside-accessible tools are also nice, but if the tools are fully accessible when the tool is closed, that would be almost as good.