I’ve been using Aweber for about 2 years on 2 blogs now and I’m really happy with it. One uses a follow-up broadcast (i.e. every 2 weeks a new “how-to” is sent) and has just over 1,000 subscribers (from about 50 when I started a couple of years ago) while the other blog uses a blog broadcast (it sends out an email with the week’s news) and has about 250 subscribers.
With its user-friendly templates, anyone who's dipping their toes into email marketing waters would love Vertical Response. Each campaign that you published with this software may be hosted for free online, allowing you to share links of previous campaigns even to non-subscribers. If you want to design your own emails, you can quickly make your own through the in-app image editor with filters and special text options.