The biggest safety issue with clipless is whether you remember how to disengage your feet when you stop. Once you have this beginner's problem licked, you are probably fine. (For the record, I still use old-fashioned toeclips. I do think it is much safer, as well as more efficient, to be strapped, clipped (or "cliplessed") than not. The only reason I have avoided converting to clipless is that I am feel too klutzy to have some bikes with toeclips and others with differently-releasing clipless systems, and I do sometimes ride the mountain bike or my commuter in street shoes.