Of course you know if you shoot a twin cam it will definately be faster but you lose reliability,tunability and you must constantly tinker with the twin cams I have owned both and know from experience that the single cam is a little slower and almost adjustment free but I'd rather have a slow hit than a fast miss!!!!
As many have said each have their advantages and disadvantages. I currently own a single cam and though its been a very reliable bow, I did have to twist a cable up to get it back in sync. I owned several twin cams and they were great bows. Since then the quality of string material has really been upgraded. I would have no 2nd thoughts at all of owning another twin cam!