I installed Amber yesterday, and it was not smooth. It downloaded the update once, but could not install as it ran out of space. I uninstalled some apps and tried again, and this time it worked (but it downloaded the whole package again, and took a lot of time).
The good part is that there is a Call & SMS filter, Glance screen, and other features, as promised by Nokia, however, on the flipside, WhatsApp notifications are again delayed. Also, the Nokia video uploader app does not work - neither does it upload, nor does it have any option to trim videos.