I'll have one of each please. :D

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.