For all its worth I just upgraded from the AGV Ti-tech to the Shoei X-11.
I found the AGV too noisy and fit was just not right, one ride with the Shoei and I knew its as near to perfect as I could want, its very light and the finish is far superior to other brands at this price point ($1100).
The ventalation system is perfect for hot climates, and the mist 'preventor' works like it should.
I've done some research into helmet design and safety over the past five years for uni and they have come a long way. It used to be that they were all 75gm single density with tough plastic/glass, but that has changed.
The important thing to know is that price has little correlation to the level of safety of the helmet. You really have to look into the helmet design and build to know what is going to keep your melon safe.
Dual density foam (EPS) liners will save lives! It has been demonstrated to reduce deceleration of your head for similar impacts by 20% or so(translates to about 40g). I can see no justifiable reason why anyone makes single density liners still, they are not significantly more expensive to make and have vastly superior properties.
Plastic (polycarbonate or other) shells were shown to transmit 20g less to your head than composite glass ones, this is a significant difference. Though glass looks nicer the properties of glass aren't great for making helmets out of. Plastic helmets have always been quite cheap as the manufacturing cost is low, the properties of plastic are however ideally suited to helmet construction.
Here are some lengthy articles that discuss why this is the case.
In Aus we have the Stds Aus requirement, these standards are almost identical to Snell requirements (Stds Aus are a lot more high tech and reliable). This means a Snell sticker on a lid sold in Australia it means nothing.
In the end of the day helmets are more or less "tuned" to impacts of certain strengths by manufacturers, this involves compromising the helmets effectiveness at other impact strengths. The ECE standards are much softer than Stds Aus, built for accidents that the rest of your body might just survive. They are in my opinion superior but the best thing you can do is find a lid that passes both ECE and Stds Aus, you'd get the best of both worlds (this used to be impossible but is now possible with the new dual density liners).
Take a good look at the HJC CL-14, though it's a mere $350 Aus, I think it may be the safest helmet on the market in Australia, sadly my attempts to get actual impact attenuation figures from Stds Aus/Snell testing have failed. Here’s a comparison between it and a Shoei written by a guy on another forum. http://www.perthstreetbikes.com/psb/index.php?showtopic=16189
I'd also like to see the Plastic version of the Icon Mainframe make it to Australia, it is made to similar safety standards.
My data is only from extrapolation from the few comparisons/studies done and thus only a theoretical advantage. Sadly helmet manufacturers are very market driven they do not give out enough reliable information to make a better decision. There are some manufacturers with very big claims that have not supplied helmets to independent testers to verify.
Hope that helped, I'd be happy to go into more detail about anything if you want.
The articles are realy informative especially the blowing the lid off one but when you do read them remember that the independant comparisons tend to test helmets at an impact they are not "tuned" for, or as with the blowing the lid off they test all lids at one of the blows that Stds Aus/Snell use two of. So you really have to take a lot in and try decipher what it all means. Thus the DOT only helmets perform very well in the single blow test but would provide little extra protection if you get another whack around the same area (estimated at 10% of accidents)
I am interested in safety primarily, those features i mentioned are enough to make a real difference. I find all lids comfy, but noisy and without enough ventilation, i haven't found one yet thats not. I do think they are insulting my intelligence a bit selling me what is effectively a small esky for $A1300.
Well I've re-read the blowing the lid off article and would recommend everyone take the time to read it. It's not that long and is very well written and informative. Thanks again to Dr Evil for posting it.
I look at it like this, I payed a lot of money for my bike because it is the best bike there is. If they wanted more money for a shitty kawasaki i would not have paid it, i would still have bought the MV.
I think the same with helmets, i don't care that the lid costs $1300 i'm going to buy the best one there is, if that costs me $350, so be it. I want the best, not to be taken by a ride by some shitty advertising company.