I haven't because I was all over the place. Lack of time and chasing users didn't work out for me, now I'm more focused on what really matters and the quality of my work, users will come
Depended on product. The one with less success was due to being too close / lack of UX. Basically saying, the mobile app's features were hidden therefore confusing the user. We we-designed a bit and are scheduled to re-launch in a few months.