EEG SMT VS. EEG ASM

[thebobpie]

Sorry I'm a newbie, so the question is stupid.
With the digital EEG ASM and the analog together, built with this tutorial(including other stuff like electrodes): http://openeeg.sourceforge.net/doc/SimpleEEG/
The cost comes to about 200 dollars.

However, with the EEG-SMT, it's WAY cheaper than 160 dollars for the ASM, so is it inferior in any way to the ASM?

Also, what are channels in EEG? Are they each electrode?