I am a strong believer in safety gear. I won't let Suzy ride with me unless she has at least full-length pants on, and long sleeves. I won't ride without a full-face helmet and an armored riding jacket. If I am riding any further than a mile or two, I always put on full-fingered gloves and a pair of boots. For longer trips, I have a pair of armored mesh overpants I can wear over shorts in the summer, giving me better protection than denim.
The first helmet I bought was a used Shoei RF200. It's internal padding was falling apart (I'd get foam crumbles in my hair when I took it off, so I added a cloth liner to cover the foam) and it was a bit too small for my head. The forehead padding was also missing, which allowed the forehead vent holes to press nice little circular indents into my forehead. With Suzy's increased interest in riding, and the fact that my full-face Seve0Seven helmet managed to get rather scratched up after the first year, I began researching helmets.
The Seven0Seven helmet I have (at top-right) was relatively nice, and I wore it through all 4 seasons. It has a chin dam, which really helped the wind noise, and never seems to get in the way. My main complaint was the lack of ventilation. I was forced to ride the entire summer with the face shield cracked open one notch (several detents allow for plenty of options in that area) so I didn't roast. In the winter, it fogged severely, and though I use an anti-fog cleaner regularly, I almost always had to crack the shield open unless I was moving quickly. I do like the snap on the chin strap that allows the slack in the strap to be quickly secured against flapping.
For Christmas of '09, I got a new helmet to deal with all of the complaints I had about the Seven0Seven. It's the GMax GM68 (lower right). It was ranked by Motorcyclist Magazine as the top helmet in 2008. It has vents like crazy and includes an LED fixture in the rear that flashes (3 different settings) to get people's attention. I've already had several people ask me where I got it, so here's a link. It's much more comfortable, especially around the ears. It also has the chin dam, and the visor hinge seems a bit higher quality that the Seven0Seven's.
Enough about me and my helmets -
I know about the DOT and SNELL ratings, but the very fact that a turtle-shell can get a DOT rating tells me it doesn't mean much. I did some digging, and found an article, published in 2005 by Motorcyclist Magazine. The article is entitled "Blowing the Lid Off". I STRONGLY suggest that anyone who cares about helmet ratings and safety take the time to read this entire article. Though it does not directly attack the SNELL rating system, it does make a case that it's not all it's cracked up to be. In fact, the results of their study caused several helmet advertisers to pull their ads from the magazine, because they suggested that the higher-priced SNELL-rated helmets were, perhaps no better (and sometimes worse) than the less-expensive DOT-only helmets.
Suzy wears glasses, and has to remove them to don/doff the helmet. I have thought about the idea of getting her a modular helmet, but I question the safety of the modular design, in comparison to the full-face. The fact the chin bar pivots on two small points seems to lend itself to an inherent weakness. So, I have started to gather some information on the possibility that convenience factor of the movable chin piece of a modular helmet might also be a safety concern.
The chin piece is secured to the side of the helmet, usually by a pin of some sort, and latched in the down position by some kind of front-facing mechanism, operated by one or more buttons on the front or side of the outer shell. This allows the rider the use one or both hands (depending on the model) to lift the chin piece above the field of vision. Of course, this should NEVER be done while riding. The front-facing latch can be made either of plastic or metal, and it has been reported by some riders that if the helmet slips out of the hand and drops (even 2 feet) onto the chin piece, the latch CAN let go and be forced open on some models.
This site performed a series of tests on several modular helmet brands and compared them to each other. I really like how they mentioned several things to be aware of when purchasing any helmet, like the ability to remove or "roll off" the helmet from the head with the strap tightened. At this point, the only things I have been able to find are opinions and conjecture about the same concern I have. There is no official way to test the integrity of the chin piece of a modular helmet at this point. Snell has not rated any modular helmets, and DOT is not concerned with protecting that part of the body.
As much as many people say we just have to accept the risks, and wear whatever we feel most comfortable in, I would personally like to determine HOW comfortable I should be with a modular helmet, compared to a full-face. If you have any scientific studies or information other than personal opinion or conjecture, please feel free to E-MAIL ME and tell me about it.