After spending a great deal of time in this space, I can say only that there are no clear-cut answers. Outbound email management tools are everywhere. Many individuals, like myself, even write and develop their own email management solutions. I've been polling people for more than a month on what solutions they use, have used, or know about, and I've received information on more than 100 solutions or providers that are active. Some of these solutions are very unsophisticated, while others are extremely elaborate.
Sophistication usually is accompanied by an increase in cost.
That's why I usually recommend the service-provider approach. This allows you to get your feet wet, and you can determine what's working and what's not. I would also advise you not to choose a provider that requires signing a long contract that ties you into something. Your needs in the realm of email marketing may change as you move further into this world, and your initial service provider may not be the provider that can grow with you. In an upcoming article, I'll analyze the functionality of software and solutions and help you determine the features you need and the capabilities that are available.