I've used both for about more than a year!! I have to say: learning Medibang was much easier than Krita. There are a lot of controls to learn with Krita so the learning curve was hard for me. My art looked choppier at first during the transition. ;-;
However, Krita has a great animation workspace for free! That's why I switched. Also, my art has gotten more detailed and professional looking after overcoming the learning curve. :D I'm still learning more about the controls even after 2 years of use, but I think the difficulty actually helped my art. 'u'
Personally, I think Medibang is more intuitive for artists, but Krita is great for pushing out of your comfort zone because there is always another feature to learn! Medibang is better for beginners, and Krita for people who want to advance, imo!