I use Xfce for a few years now, that's why I'm asking.
I used Xfce and switched to i3. I can't imagine going back whenever I'm in Linux. My work environment is MacOS and its frustrating having to manually move windows and like others have said is just plain clunky after having used a tiling window manager. It did take a bit of time to get used to i3, but once I did it was glorious.
Yes, although with modern processors, GPUs and memory prices that is probably not an issue.