I have found the one big feature of Ubuntu that I miss in Debian is PPAs. Other than that it's largely the same. Configuring the system requires more file editing and command line work than I remember with Ubuntu, but the documentation helps quite a bit.

EDIT: By default, non-free drivers are placed in a separate repository, and receive less support. In my case the biggest pain has been Nvidia drivers. I needed a cheap card to drive an HDMI display and all they had at the store was a GT710. That meant installing the proprietary drivers, since the free alternative had poor performance last time I checked. Every few updates it breaks, and I need to reinstall it and sign the kernel module each time. That is something to watch out for if you switch over.