The issue with DIY is that you can easily get black listed by a major ISP. If enough idiots mark your "Welcome to MyService.com" as spam, you are screwed. Once

The issue with DIY is that you can easily get black listed by a major ISP. If enough idiots mark your "Welcome to MyService.com" as spam, you are screwed. Once done, nobody at that ISP is going to get your mail. That's the advantage big players like aweber have, they can pick up the phone and work out issues like this with an ISP. BTW, its worth subscribing to campaignmonitor to actually see which ISPs are nuking you globally.