What are some alternatives?
Interseller - Interseller helps find contact information, reach out to them with email automation and syncs it all into your database.
SendInBlue - Innovative online Email Marketing solution to manage your contacts, create & send your newsletters and track your results. More than 80 000 clients. Best prices and attractive features.
Front App - multi-channel inbox service for collaborative teams
MailChimp - MailChimp is the best way to design, send, and share email newsletters.
Mailmeteor - Send hundreds of personalized emails with Gmail.
Marketing Optimizer - Optimize conversion rates, increase lead-to-close ratio, and resell leads easily. Includes complete WordPress integration.