I think it's great that they are going to officially support iOS again. Coincidentally I submitted a new version of my own browser app to the AppStore, on the same day they made the announcement. I added support for the new Firfox sync protocol - it took me forever to get it working and now it's kind of redundant :-/ Anyway, if someone is interested in the source: https://github.com/graetzer/Foxbrowser
This is on an iPhone 5S running iOS 8.1.1, with about 200 bookmarks. If there are any crash logs I can provide, let me know.