There are quite a many email service providers on the internet but to pick the most convenient out of them is an uphill task and I can detail my experience which will help you learn about them and decide for yourself:
Sendinblue.com is a really good SMTP relay service providers than can be handy if you are looking for sending both transactional and marketing emails. It also includes email and SMS marketing services and provides an option to track the email campaign results and make necessary changes if you might.
Pepipost.com is a good email server for sending bulk emails and in a lesser time frame. It gives you two modes of delivery- SMTP relay and Web API to choose from. As it uses both SSL and TLS encryption, it provides a very secure environment and doesn’t store your data, thereby eliminating risks of the data being stolen or leaked.
Mailjet.com is a reputed email server that allows you with the options of sending, delivering and tracking your emails to a huge number of recipients. It allows you to integrate their API and lets you create newsletters and other marketing campaigns quite easily and quickly.
Amazon SES provides you with a very easy way to send transactional as well as marketing emails by making use of their email addresses and domains. It provides you with the facility of sending thousands of emails with a single click, thereby saving your costs and energy. Amazon has a strong email filtering technology which makes sure your messages won’t be blocked by spam filters.
Binaryclues.com is a popular email service provider which helps you with designing your email marketing campaign by their swift bulk mailing software which allows you to send, receive and track your emails very effectively and most importantly, the configuration it provides is quite easy and needs less maintenance.