With spectacles, not only are you stuck with a frame on your face which you get to push up all the time if you sweat a lot, but also you only see well in a limited field of vision.
Contacts, on the other hand, let you see clearly all around you (they literally correct your whole field of vision) and once you get used to them (it didn't take me much longer than a month or two at most), for 99% of the day you can hardly feel them on your eyes. Basically, it feels like seeing clearly without wearing anything.
It's been almost a year since I started successfully wearing contacts (I had tried two and a half years ago, too, but ended with a nasty infection after having worn them a few times - wrong lens care solution!) and I can't think of a reason why on earth I'd want to go back to glasses.
Mind you, if you have sensitive and infection-prone eyes like mine, you do have to make a few sacrifices. I switched to a brand of soap which has no perfume or colour in it whatsoever, and also I cannot use any lens care solution because I'm sensitive to boric acid, an ingredient in most multi-purpose solutions. AOSept, a hydrogen-peroxide-based system, works fine for me though and I also feel surer about the sterility of my lenses. Oh, and did I limit I have a very flat cornea? That kind of limits the range of disposable contacts I can wear but I have managed to settle on Frequency 55 Aspheric which provides me with good vision and unparalleled comfort.