Whats exactly the use of clipless?

Clipless are like ski bindings for the bike. You essentially step into a mechanism on pedal (typically) that helps hold your shoe to the pedal. This typically gives more control of the bike to the rider and allows for more power to be transfered as you can get power on the upstroke as well as the downstroke.

Personally, I love riding with the clipless and don't like riding without them. They make me feel connected to the bike. Also, as long as you don't crank down the tension, they're easy to get out of. It's part of the set-up though as you need to make sure you can sprint without comming out while being able to unclip if something happens.

My friend recommended riding with one leg clipped in at a time so that I could get used to the circular motion that the clipless allows. I believe this helped on many fronts. It helps with trying to get power out of the complete stroke and, with one leg out, it helped with confidence as I could quickly put one foot down if needed. Of course, I did look funny with one dangling off trying not to get hit by the crank/pedal.

That's pretty good advice. I trained myself to pedal in circles by staring at my front wheel while I climb on my road bike. For some reason that helped smooth out my pedal stroke alot. I don't recommend doing this on trails obviously.

I hate riding more than a few miles without my clipless pedals. It feels so inefficent.

Thanks for that. Im gettin a new bike in a few days or so and it comes with clipless stock. My first time riding clipless. I take in that advice and think it will teach me to get max power out of every up/down stroke. THANKS!

I got the candy's and use a soft-soled type shoe. I HATED them at first: couldn't clip in worth a dang and my knees hurt. I moved the cleats back to the more rearward postion on the shoes and can now clip easly and my knees don't hurt. I'm loving them.

I'll have one of each please.

In answer to the question:

pedaling your bike: much better
manuvering your bike over obstacles: maybe better, maybe worse
bailing off a stunt: much worse


YMMV

Personal preference and riding style strike me as some of the driving factors in the decision to use clipless. I ride XC, my preference is to use clipless.

I started using clipless when I bought my Blur in '05. The pedals are Shimano M520's. It was awkward at first. I started with the tension all the way out so it was really easy to get in and out. I learned pretty quick this way. I have since purchased a second pair for my commuter bike. Riding with out clipless pedals doesn't feel natural anymore. They help keep my foot positioned properly and on the pedals. I still fall occasionally, especially when I've stopped quick and didn't think to unclip or if for some reason my brain just isn't focused and I go to stop and don't unclip until I am already tipping. Though these occasions become rarer. I believe the M520's come with cleats already. I'd say try it, give it some time and then decide which you like better. I'm sure there are those here who used to us clipless, went back to platforms and decided that is where they wanted to be. Is it worth $100? With out a doubt. You could probably sell the pedals if you don't like them.

From a safety standpoint, IMHO, clipless keep your feet on the pedals, especially when the crank hits an object like a log or root big enought to be a log. I've had it happen where I'm out of the saddle, the crank hits something and I can feel my foot lifting but the cleat holds it in place, could be a new adventure in pain if it wasn't for the clipless.
There are times, like riding through a rock garden, when I'd rather have flats but 90% of the time I'd rather have clipless.