Asterisk vs. sipX for newbies

Hi

For those out there who have good experience with both solutions, how would explain to newbies which to use in which context?

There’s a document over there entitled How to Compare sipX ECS with the Asterisk PBX (sipX vs. Asterisk), but it’s a bit too abstract for people who are just beginning to learn about VoIP.

The only difference I see at this point, is that sipX doesn’t support FXO cards, and hence, requires getting FXS-SIP boxes to connect the LAN to the POTS.

Thank you
Fred.