Servos are fun to work with. I use them in some of the robotic stuff my son and I play with. If they are unmodified, as in right out of an RC car there is really no speed control. There is a variable resistor in it that is used for positioning. If you hack it, remove the variable and put in two same valued resistors and removed the mechanical stop, you can now use the servo as a bidirectional motor with speed control. I have never played with the PICAXE. If it has servo commands built in that is wonderful. At times it came be a pain in the butt to get them working properly with a PICmicro because you have to use the PWM feature which is not specifically for a servo control.
All this stuff is fun!!!
There are 10 types of people in this world. Those that understand binary and those that don't.