Bump.
I came down with a case of helicopter fever, and purchased a Blade mCX2 4-channel helicopter recently. After a bit of practice and two new battery packs, it's a riot to fly around the house! It's no bigger than a Syma s107, but flies so much better! It's faster, more agile, less susceptible to turbulent air like from a heat vent, and far more responsive to the controls. It ought to at roughly 5x the price.
One of the original Syma helos bit the dust with a non-working tail motor. I may repair it. The other few I have are still kicking, and still get actively used. Although, the Blade is an absolute riot, so that's what I'm flying mostly now.
To sum up the differences for what you get for 5x the price of a 3-channel Syma s107 when buying a 4-channel Blade mCX2: A helicopter that flies like a real helo, not like a 3-D R/C car. Is it worth the price difference? For kids and others who want a simple, durable, easy to fly helo, no. For folks who have the hankering for something better after they've gotten good with a s107, yes.