I have a Gerber. My kids got me one some years ago. I broke two and Gerber replaced them. I keep it at home to use around the house and use a $ 15 clone at work because I don’t want to accidentally leave the actual one in a box that I have opened.
Let me also throw out Sheffield as a sort of starting place. I had one of their sets that included either 7 or 9 different pieces – from the standard Leatherman style pliers and a larger wrench multi-tool down to a 4 function “Swiss Army” style keychain. The tools aren’t the best quality but they aren’t bad and it gives you a chance on the cheap to test drive a range of ideas.
The US Air Force has probably issued me a half-dozen multitools over the years (thank you, taxpayers!), and I definitely prefer the Gerbers’ method of accessing the pliers over the Leathermen’s.
With a Gerber you store the end of the pliers downward in the sheath on your belt, then when you need it you grab and flick them straight down. There’s a very satisfying feeling to it, and you can have access to your pliers in less than 3 seconds usually. I believe almost all Gerbers are set up this way.
Most Leatherman tools have the pliers on the inside of the tool, so you have to unfold it much like you would a butterfly knife. It’s possible to get a Leatherman oiled up enough that it’ll fold and unfold easily, but it takes MUCH longer than with a Gerber, and even when you get it to that point, it still takes a little bit of dexterity in your fingers.
Basically, I’ve used both, and don’t know why anyone would pick a Leatherman over a Gerber, because you can find a Gerber that does the same job as whatever Leatherman you’re looking at, and it’ll be easier to use. Gerber also makes one with a C-4 punch and blasting cap crimpers, and that’s the only one I ever actually use.
ETA: Oh, and you can close the Gerber easier with one hand as well.
The best tool is the one you have with you. I find the big Leathermans and Gerbers to be too bulky for daily carry (though I keep on in the glovebox). I used to carry a Leatherman Micra daily until I lost it. Now I have the Gerber equivalent (who’s name I forget).
The Leatherman is better, IMO. The Gerber is held together with little bolts that tend to unscrew themselves.
I have dozens of knives and mulit-tools, but the best quality by far is SOG.
They have many to choose from, and they are tough, and come with the sharpest knives you’ll ever find on a MT.
For pocket carry when a big tool is too much, I carry a Leatherman Squirt P4.
Leatherman makes good tools too.
I have the Leatherman Pulse, which is a fine tool. If it needs to be replaced at some point (it’s 8 years old now, and in great shape), I’ll likely go for the wave… or that sexy Paladin tool Snowboarder Bo is pimping. I don’t do that work right now, but I want a punchdown tool on my multi-tool!!! 
I carry my Leatherman on my belt every day, and it’s rare that a day goes by that it’s not pulled out for something or other.
I keep a Leatherman Flair in my glove box (I don’t think they make it anymore, but it has a corkscrew that has come in very handy over the years…) and a SwissTech Utili-Key on my keyring. It’s surprisingly tough useful and takes up no more room than a standard key. The only issue I have with it is that it’s very easy to cut yourself opening and closing it.
This thread caused me to buy a Leatherman Wave this morning.
I received the Leatherman Charge TTi for Christmas last year and I use it all the time. I don’t necessarily carry it with me unless I am actually doing repair work but when I need to fix anything around the house that is my go to tool. I haven’t used my old pliers or screw drivers since last year.
I am in the Gerber camp.
IMO Gerber and Leatherman are interchangeable, but I prefer the flick access to the pliers in the Gerbers to the Leatherman fold.
My main beef with multi-tools is that they always have the useless Philips head screwdrivers and never a Robertson.
When are you Americans going to learn that Robertson is the only way to go?
It depends on what you are looking for, I am a machinist and do lots of remodeling work and find most multi-tools too light-duty. I have been very happy with my LEATHERMAN SURGE. It’s bulky but takes a lot of hard use.
I did cut off the screwdriver bit holder that takes only Leatherman bits and welded on a socket that takes regular screwdriver bits.