Some good information is really missing here. You talk about $600 helmets, and how this Suomy is cheaper, but you don't really say what Shoei, Arai helmets you are comparing this to for "top of the line features".
I have a Shoei RF-800 and it is very good, better shield replacement, and only cost about $250 (good mail order price, not $300+ retail price).
Somebody said when you buy a Shoei or Arai you're paying for the name. But I would suspect both make varying models, entry level, midrange, etc. with different prices and features.
You say this is a $400 helmet, I bet I could get a good comparable Shoei or Arai helmet for the same money.
Your own review of the RF-800 indicates its pricing and value ("Not only is the RF-800, at an affordable $268.00 MSRP for solid colors and ranging from $345.00 to $387.00 MSRP for advanced color schemes and race reps, a "best buy", it may be the best buy of any street motorcycle helmet. ") I consider it a midrange helmet. Of course its been replaced by a new RF-900, and they also have other new models.