The picaxe chips use pic microcontrollers exclusively. They have the BASIC code set bootstrapped on. The advantage of this is that you need no special programmers, so you can get into programming them cheaply and easily.
In addition there is a free software tool for coding which has a built in emulator, so you can test the code out before flashing it to the actual chip.
Some of the latest versions can be clocked up to 64mhz, which is no slouch. For most purposes 4-8mhz is quite sufficient I have found- they crack through the code quicker than I can react.
I was a complete programming neophyte up until I encountered the PIcaxe chips. I had a go with OOPIC, and couldn't get along with the object orientated programming at all- found it totally counter intuitive. I also looked into PIC's programmed with assembler, but that looked like hard work. The Picaxe has routines built in for decoding R/C pulses from the RX and controlling servos, in addition there are simple to use routines for things like I2C and serial control, which is useful for interfacing with servo controllers like Pololu boards alongside other serial controlled devices.