I have been riding fixed and ss for a while now (fixed front brake and ss both brakes). I find fixed more fun, but I just can't see how anyone can call it safer in traffic. The argument I have heard is that the rider gets more feedback riding fixed so they have more control, unless you don't know how to use your brakes properly this shouldn't be much of a factor.

Like everyone says though, give them both a try and see what you think.