As most previous reviews said, this pair is very comfy with nice and snug fit.  They are perfect for Zumba, since they allow my feet to flex and let me turn easily without tacky bottom.  For the same reasons though, I don't think they will make good shoes for other kinds of indoor exercises that require tacky soles and/or solid support (i.e. spinning, running, etc.)  I wear size 7 normally, but 7.5 on this pair fits me perfectly.