like, what about them? just they have both male and female seed. feminized they only have female seed. that's the difference. are they better? genetically different (male and female) individuals vs genetically similar( all female) still different, no real difference there, only when you buy regulars you get males too. so if your doing flowers there is no need to buy regular seeds if feminized are available.
it all boils down to your intent, want seeds get some reg's to have a male for pollination. if not there really is no reason to buy regular seed. Some believe they are better some how, can't see how. i will get regs or fems depending on what I am looking for sometime reg is the only option
they say regular seeds are considered more stable in terms of genetic expression, also they have a tendency to produce plants that are less likely to exhibit hermaphroditic traits or other undesirable characteristics