Optimonk is really helpful to improve the revenue of our store! Great way of showing the offers to the end customer using this app. We really love it ,

Awesome app! Helps me grow my email list. Could have a bit better design functionality, but awesome app!

It's pretty good - simple to set up and the fact you can A/B test different designs is great.
One drawback though; it's slow to load and that does impact on site loading speeds. OptiMonk are aware of this and are working on fixing it but it is a caveat.