RSS has been dominated in the past by Feedburner (which is a digital property of Google) and there have been few viable solutions outside of it for Web workers to utilize. Feedburner's RSS to email features have been lackluster at best. Fortunately there are quite alternatives that you may want to consider.
The first place to look of course is directly to your email service provider. Most ESP's offer the functionality. Some of the most popular, currently, are from vendors including Aweber, MailChimp, Constant Contact, but there are many others. Oftentimes however, those publishing their RSS to email are also interested in monetizing their content. A solution from RevResponse caught our attention and it may just be a perfect fit for marketers.