My friend loves them, he always has his Gerber on him and uses it for everything. IMHO the Gerber is beter than the Leatherman because you can flick it open with your wrist. By the time I get my knife out on the Wave to cut anything, my friend has already done it with his Gerber.
I ruined a Leatherman supertool in about a month. It seems the pliers are not designed for actual work and they bent. Than I bent the screw driver trying to take out a tough screw, and broke the beer bottle opener. Also it rusted like crazy! Now I have a Leatherman Wave that sits in my desk draw and opens box's and letters, which it seems well suited for. A $70 paper weight.
To me they are to expensive to actualy use, heavy to carry, and all the tools are really light duty.
I use my utility knife for work, because I can cut rock with it and replace the blade 6 times a day. Also its only $14 so I hammer with it and beat the living piss out of it. If it lasts a year I'm happy. I had a big knife for camping, which has been replaced with my new Ka bar, thats a real knife.
I have not found multi tools to be up to the work I do, they try to do everything, but can't do anything well.