maps apps is finally feature complete I think, not smooth as here drive or as reliable as the old maps, but that's the default system wide for everything windows 10
similar with the new camera, lumia features but loses the rock solid stability and swype back to see last shoot-cameraroll, I've got a feeling that groove app is good, but the OS itself is dragging it down
Cortana now fully syncs with pc version, at the cost of everything else it had going for it on 8.1, its just a bing.com wrapper now
cant think of anything else now, other than i'd love my action center to sync between w10 devices, if I could see some derp texting me on wasap on my pc and reply to it right there, that would be great, and instead of a funky onedrive app the file manager app should act as the w10 pc explorer, so I can browse my files + onedrive files seamlessly