Comparing outgoing mail options, self hosted VS google apps in my situation

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http://serverfault.com – I am setting up a small site that has the need to be able to programmatically send mail from time to time. Password resets and things like that. I'm already using google apps to handle my domains email, so now i'm left with the decision between setting up basic SMTP services on my server to send "password reset mails and things like that" OR instead to have the software use google apps to send mail. I like the google apps option as it's less stuff to worry about and seems to fit my needs, i'm trying to figure out what the downsides would be? Thanks for any thoughts (HowTos)