I doubt if the serrated blade is for bread becaue that is all mine came with and I don't do bread in a meat slicer. The serrated blade is so that it stays sharp. As for the non-serrated blade, all I can suggest is RTFM.
I have this one. Do I justify the price? well the way I see it you can't take it with you... Do I use it Yes. This is a medium duty slicer and works very well.I will have to say if you have one they come in very handy, for all kinds of slicing.