I use CampaignerPro (www.campaigner.com). Decided on them for cost vs. functionality. Pretty robust software with low cost for our volume (30K emails a month).
When looking for an email marketing solution you should make sure you determine your n...
Have used a few over the years - currently liking MailChimp for their strong API support (we integrate it into our signup process) and lack of forced branding in the outgoing emails. Many of the other services stick their logo at the bottom of you...