Not all third-party e-mail services want all businesses as their clients. The type of business you have is a deciding factor as to which e-mail service is most appropriate for you. For example, while we love MailChimp as an e-mail delivery service, if your e-mail news information includes information with “affiliate links”, or your business is a multi-level-marketing business, then MailChimp is not for you, as they do not allow those type of businesses, among others, to use their service. It is critical to take into account these type issues in making a determination of the best product to use.
Cost is, of course, another factor in determining what the best e-mail service is for you and your business also. There are some e-mail services that offer “free” programs which cover a small number of e-addresses and set number of e-mails sent per month. These may be a good choice if your business if you are just developing an e-mail list if you business is not a type that they forbid to use them. And you can always upgrade to a paid version as your business grows.