how good are ESKY rc helicopters?

whats the best make of rc helicopter? i want one thats big and strong. How good are ESKY? and whats the difference between a 6ch and a 4ch?

They make a helicopter called the Belt-CP, and it is the biggest ready to fly helicopter they make. If you are a complete beginner I would recommend starting with the Esky Lama V4;
http://www.xheli.com/2-4ghz-lama-v4-silver-version-.html

Very easy and great learning helicopter.

4 channel helicopters go up and down by changing the speed of the main blades.
6 channel helicopters change the pitch/angle of attack of the blades.
http://www.rcdiscuss.com/index.php?topic=68.0

Good luck!