They are all ok in that they all meet the same safety standards - so they are pretty much equally safe. I would probably try the Giro Savant or Sonnet first (we are talking about road biking, yes?), although it would be best if you could find an LBS that carries Giro helmets to try on first. "Women's" doesn't fit all women better, and you want to make sure it's the right size.
The "nutcase" helmets are really skating helmets designed for multiple impacts. You don't want those. I'd look at the Giros as they are designed for cycling
I agree that you should purchase a bike at your LBS, It isn't like a pair of shorts that you can wear if they don't fit correctly. It needs to fit perfectly. The LBS can also help you adjust it properly.
The "nutcase" helmets are really skating helmets designed for multiple impacts.
Nutcase used to make skate helmets designed only for multiple small impacts, but those were not the ones LLB sells and they also no longer make them. The ones LLB sells are CPSC certified (one high impact crash) only, while the skate helmets are dual certified for one high impact and multiple small impact (ASTM). They've improved their ventilation, but they are still don't have anywhere near the airflow of a typical bike helmet. They're very easy to get a good fit with because they include so many sizes of pads, but you have to know what a good fit is and many people don't.
*I don't wear a Nutcase, but my DD does. I don't really do much biking, I skate, but when I do I wear an S-One. Most of the people I know who used to wear Nutcase switched to S-One (for skating and biking, likely because we can't skate in bike helmets but we can bike in dual certified skate helmets and it means only needing one helmet) after Nutcase failed some of the certification tests. Personally, it makes me leery of the company.
I don't even know where to post an intro here! I was on TK/TN/TB since 2003, mostly local boards. I was m_and_m.
"I speak without reservation from what I know and who I am. I do so with the understanding that all people should have the right to offer their voice to the chorus whether the result is harmony or dissonance. The worldsong is a colorless dirge without the differences that distinguish us, and it is that difference that should be celebrated not condemned." -Ani Difranco