I have a pair and I love them, best advise is to start out slowly to avoid injuries. I just completed my first 1/2 marathon in them and it was awesome. Now I'm the proud pappa of a few different pairs of Vibrams
Below is a great article on how to get started with them and avoid injuries. Hope it helps you out.
The Vibram's are a great training tool or running shoe, but they still have enough padding and rubber on the bottom to get us into trouble.
Try this out, stand up from your desk and stomp your foot straight down on the ground...feel the jarring sensation going up through your spine.
Now put your foot out about a foot in front of you, and stomp down onto your toes (landing about a foot in front of you).
Feel the difference?
When you land on your forefoot (what I call toes, but it's the entire area including your toes and the area behind your toes known as your metatarsals) you engage the most magnificent shock-absorbing mechanism known to man, or to perhaps any animal on the planet...and that's because as bi-peds, we have to handle more force, with less legs.
Landing on your forefoot you use your arch (the only part of the body that gets STRONGER under tension), achilles, calf, quad, hamstring, and glute, as one giant 2-3 foot shock absorbing, and rebound (they call it 'loading') mechanism.
Unfortunately, when you land mid-foot or on your heel, you lock out the entire spring mechanism...aka, that's why the jarring shock travels up through into, and through your spine.
It's also why people get knee pain, tendonitis, and so many other problems...it's because we've locked out the body's natural shock absorbing mechanism.
The trick is, when we first do this, if we've been shod all of our lives, it doesn't feel natural. To some it does, but to many it's difficult, and to almost EVERYONE, even professional runners who try this, it'll cook EVERYTHING in your feet, achilles, and calves, QUICKFAST.
Learning how to run on your forefoot means learning how to run all over again...it doesn't mean you're starting from square zero, but you, and in particular, your muscles, joints, ligaments, tendons, and BONES, have to learn an old dance (we all knew as a kid first learning to walk and run...just watch them, they're ALL on their toes...some can't even come down on their heels and are sent to physical therapy at age TWO to try and get their heals down...yikes!), you have to learn an old dance all over again.
This means going slowly...even, or especially with strong muscles, because even if they can handle it, the attachments, such as that amazing rubber band, known as the achilles tendon, are NOT ready for it...and even if the achilles were, the bones themselves wouldn't be ready. This is why you have to start slow and let the weakest points build up first.
I've had so many runners say 'I'm not meant to run on my forefoot, my calves burned out and they, or my achilles were killing me for weeks.' They're right, you're not meant to run FAR on your forefoot to begin with. When I started, it was with 100 yards, and then I rested...but within three months I was running a fast 10K, and w/in six months, over ten miles. But I started by taking baby-steps.
I recommend baby-steps...specifically, getting up on the forefoot and using your body's natural shock absorbing mechanism, RATHER than your back.
Of course, watch for proper form too, keeping your core engaged and standing tall...but I'm guessing, even if you were to do this, but didn't change your stride, you'd STILL be in pain.
I hope this helps, and you're off and running. Thankfully, it's winter time; what better of the year is there for starting slowly, and building into the strongest, fittest, fastest YOU ever!
Go have some fun, and keep us updated!