It's not the email side of the problem that makes the difference (after all, sending an email and processing bounces and unsubscribes isn't rocket science).
It's about selecting the target groups based on the data in your CRM system (what they bought, if they are likely to do repeat buys, if they pay, if they complain a lot), their click behaviour on the mail (do they read it, do they click on links), what they do on your site (how much visits, what pages do they look at, how much time to they spend on your site) and possibly their presence on social media.
So the important thing is integration with your CRM system, your site and your Facebook page. Since you tell nothing about those aspects it's difficult to advise what's best for you.
Hi friends, i am looking best email marketing tool, can anyone suggest me a tool for email marketing.