I have had cheap helemts before, the last one I owned was a Cycle Gear seven zero seven, Now I own a Shoei RF-1100.
The Shoei is the best helmet I have ever owned. With the Vents closed its quiet. With them open its average with noise. The biggest advantage of all is the ventilation. On some helmets I have owned even with all the vents open I couldn't even tell if they were open.
HOWEVER with the RF-1100 I can have the vents open at 5mph and feel the airflow. While you are ridinig you literally feel the air in the canals in the top of the helmet and feel it going from front to back and towards your neck. Ventilation is SUPERB.
The issue I have found with Helmets is there is no middle ground in quality. Some cheaper helmets I have had only lasted a year. Some started having quality control issues after several months. There are only 2 types of helmets, cheap ones and then there are SHOEI, ARAI. These 2 brands actually use decent quality products to make them. HANDMADE, none of that assembly line crap.
Even when I was looking at a helmet that was around 350 from Icon, the build quality and the feel of the helmet still felt cheap. Then again, Icons are just fancy HJC's with a stupid hi mark up.
Go Here The Helmet Center Phoenix, AZ (623) 444-4789
This is a local store here in AZ that also has a ton of online reviews. The manager at the store chatted with me for over an hour when I was in there looking for my new Shoei (couldnt decide on design).
Anyways, point is do your self a favor and don't skimp on the most important piece of equipment in your arsenal. Get a Shoei or Arai. Not to mention both Shoei and Arai are always on top of EVERY new DOT and SNELL cert that comes out.