In the case that you decide to go with an email delivery service, there are some things that you should consider:
Pricing - pay by month, pay by emails sent, and lifetime license? If you send infrequently, the third option might be more cost effective.
Do they fight against spamming activity?
Do they have at least one staff person who actively works with blacklists and white lists? Can you talk to them?
Do you like their reporting tools?
Do you like working with their application?
Who are their customers? In addition, you might even ask for references, if that is important to you.
Select the service that best suits your business needs. You need a medium that can give recognition to your brand on an international platform without spending a lot of money.
People around the world must know what you have got for them. You have to present your ideas in a very good manner in front of them. Make your emails appealing, so that they can prove productive for you.