GSM/GPRS modems are cheap; so are SMS messages. The answer should be clear...
The only
thing I spec for SMS notifications is a GSM modem physically connected to
the monitoring box. There's still points of failure, but they're a lot
fewer than SMTP to some third party.
True paranoids (as we all should be) monitor their monitoring box, and it
might be permissible to use an SMTP to SMS gateway for that monitoring, as
long as you're monitoring all the appropriate things so that wide-scale
failures (such as power loss) still get to you via your GSM modem (mmm,
local UPSen).
- Matt
Professional Paranoid