So, an extended use report is in order here.
I now have about 5000 miles of use out of my Symax III. Commuting, around town errands, short rides and long rides.
First, not much use in rain. Have only ridden through rain a couple of times and it was not very long,5-10 min. So, cannot comment on leaking if any. I suspect it will leak at some point the way the sun shade mechanism is fitted on the top of the helmet. With my fairing and windshield it will take a heavy rain for quite a bit of time to get enough water exposure to show any leaks.
Wind noise. Again, I have a windshield and fairing that provides a 'bubble' around the helmet, no direct air. But, in a cross wind I do get a lot of wind on the helmet. Wind noise goes up a bit, but, still not as bad as my Shoei RF-1000 was. Wind is still not as loud as the road noise.
Road noise. After getting this helmet I also replaced the mufflers on the bike. It is quite a bit louder now. Most noticeable when open throttle on uphill roads. As I stated before, the helmet does not attenuate road noise as well as the Shoei. I think it is due to a plastic shell vs the thicker fiberglass used in the Shoei. The road noise is probably the only real complaint I have with the helmet. Yes, I do wear ear plugs on longer rides. Ear plugs do not cut out the noise, they just reduce it to non-harmful levels. The road noise is still irritating at the end of a 10 hr day and it will mask out my music on the helmet speakers.
Fit. Just finished a 7 day, 3000 mile trip. Many, many hours wearing the helmet and no fit issues at all. Very comfortable at the end of 10 hr riding days. More importantly, my ears did not hurt after a day of taking the helmet off and putting it back on many times in a day.
Visors and chin bar. The only issue here is that sometimes the chinbar latching 'sticks'. I have to push on the chin bar to release the latch. Still a one hand operation. The sunshield works well and covers the entire vision area. I don't carry sunglasses anymore. I did add a strip of black tape to the upper edge of the clear visor. That way I can tilt my head down a bit when riding directly into the sun. The clear visor has a pinlock for anti-fog. So, it works fairly well, but,not as well as I would like. I will go back to some wipe on anti-fog stuff if the pinlock proves less that satisfactory during my winter commute.
The one thing it has done is get me addicted to a modular helmet. Wearing glasses it is a great convenience to not have to take them off all the time.
So, would I buy it again? Given the alternatives, probably yes. Especially if I could get it for $100
I'd still be interested in trying a Lazer or LS-2.
I'd also still like to try a Schuberth. I just won't shell out that kind of money without knowing for sure that they are that much better.