We've been using Taplytics for Native Apps A/B testing for a little over a year now, and have found the experience to be great. They are extremely responsive to our questions, and are always willing to put in time to work with us, often one-on-one, to work through the more challenging situations we create for ourselves.
Building tests is quick and easy, and setting up for testing is also intuitive, and lets us feel confident in the test before we make the test live.
We started with the A/B testing, and Taplytics was way better than other similar tools. Now it's going a step further to fully integrate the user experience and feedback, this is just great! Helping us a lot on creating better apps for our users!