I had used Mailchimp in the past without any issues but I was pleasantly surprised with how robust hives.co is for the cost. Especially for a smaller company that is moving towards larger growth but still may have a steep learning curve with other marketing and CRM software, Hivs.co serves as a more inexpensive and intuitive option. Tip: Play around in Beta mode for a good chunk of time so you don't become overwhelmed in the live environment first thing. Makes a world of difference. Review collected by and hosted on G2.com.
I wish you could send emails through and API but it didn't make a huge difference with the company I currently work for with it. In previous larger companies, I would have longed for a bit more automation features. Review collected by and hosted on G2.com.