I am excited to try W10 on a phone. I would love to see MS hit it out of the park with W10. The app porting issues remain to be worked out though.Have you used windows 10 on a phone? They've been updating and making changes to the UI. I like windows phones, and wp8 is a solid mobile OS, though the UI decisions they've made haven't been that well received. Based on that feedback, they've made quite a bit of alterations to the UI.
I had to revert back to win8 because the latest build was too unstable to be used unfortunately.
I have tried WP8 twice in the last year with Nokia Icon and Lumia 1520. Great phones but I need more customization from the UI. They need to make all tiles be transparent and live tiles. Some of the bundled apps on WP8 do not support this. As a whole I think MS is moving in the right direction under the new leadership. I think app porting can sometimes lead to a not so great a user experience.