FP is fixed pitch - the pitch of the blades doesn't change so to go higher you make them spin faster. There's a slight delay for the motor to speed up so the heli is a little slow to react.

CP is collective pitch. The blade speed stays pretty much the same and to go higher you just increase the pitch of the blades. Blade pitch can change much faster than an FP can increase motor speed so a cp heli will react faster and smoother. It's a better system but there are more moving parts which means more expensive. The blades spin faster so in a crash you'll probably break more parts. An fp can use a cheap 4 channel radio while a cp will need a 6 channel and better/more expensive electronics all around The honeybee, falcon etc come with a radio, you'd need to buy a radio for most cp helis.

If you ignore the cost collective pitch is a better way to go. But like I said before, I don't regret starting with a fixed pitch. At some point in the near future I'll get a collective and the falcon will sit on a shelf, but I've already gotten my moneys worth out of it and then some. For me, it was a very good investment. Your milage may vary.