I am a big fan of feminized seeds because on the small scale grows I have done I don't have the room to get 5+ plants to maturity to see sex.
I have had no problems with my fem seeds at all.
I think the hermi ratio is affected by the method used to get the female pollen.
theres multiple ways to do it, but the best way is to just let a female plant keep flowering until it grows balls, you can harvest those pollen sacs and pollinate another female, or just let it pollinate itself, but I think hermi x hermi would be hermi-ized seeds, I could be wrong though, alot of people say that happened to them and they had some bomb ass feminized seeds no hermi or anything.