I'm not positive I'd wait. IPB will release the public beta in a few weeks? How long will it take for a truly stable release? 6-9 months - at a minimum ? Guess it really depends on your budget and launch timeline.
I meant to say.....You could "technically" run a mail server on any computer that has an IP. I don't suggest you do this since your IP will be blocked in no time.....regardless if you're spamming or sending legit emails.
Headaches ?! It should take you 5 minutes to set up Mandrill. We send 1+ million emails per month and have tried many solutions. We moved from SenGrid a few months ago and we're really really satisfied with Mandrill. The pricing and feature set is better than anything else out there.