Mailchimp and Mailerlite are both good Email Service Providers (ESPs.) Mailchimp is certainly dominant in the business. Their generous free plan--up to 2000 subscribers--hooks many who are then too lazy to switch later on.
Mailchimp also has the most integrations, meaning that if you're using other software and services, you can often make those services "talk" to one another easily.
But Mailerlite is catching up. Fast. In fact, last week they announced an integration with Instafreebie.
I switched from Mailchimp to Mailerlite when my monthly bill hit $150. In fact, my bill very quickly went from $75 to $150, and my whining could be heard for miles.
The price difference is fairly extreme. With 15,000 subscribers, Mailchimp is $150 while Mailerlite is $65.
Still, I was reluctant. Mailchimp is powerful, and I was comfortable with its nomenclature and functions. Mailchimp can do some things that Mailerlite can't do, particularly with regard to creating segments from your lists.
Six months later, I'm pleased to say that I actually like Mailerlite better. I find their webforms easier to use and more attractive. Mailerlite will let you make an infinite number of landing pages, which I am now using for all sorts of purposes. Here's one I made in about five minutes to host a contest. And here's one that I use to give away a free book for newsletter signup.
And I like the things that Mailerlite is still working on--their segmentation is already more powerful than when I switched. They just unrolled a powerful new automations (autoresponder) interface. And now they're working on "tagging" which will basically make their segmentation tools better.
Meanwhile, over at Mailchimp, they are working on Facebook advertising. And I am baffled. Why would I need to run Facebook ads out of my Mailchimp account when I can just run them right at Facebook? They must get a nice cut of the advertising revenue. Greedy much, Mailchimp? Their other point of development seems to be abandoned shopping cart recovery, which authors who drive traffic to vendors like Amazon can't use at all.
For authors with lists greater than 2000 members, it's hard to argue for Mailchimp in this marketplace.