Beware of the upcoming Budgie Desktop Environment, it is a serious competitor to MS Windows and Apple OSX interfaces in terms of usability. Ubuntu is going to release a new version of Unity (current is v7, going for v8) but IMHO Budgie is way beyond and could be the new war-facing Desktop Env from the Open Source community. It is going to be available in the next Ubuntu release with apt install budgie but in the meanwhile you can use,

add-apt-repository ppa:budgie-remix/ppa
apt update
apt install budgie-desktop budgie-welcome

Note: do NOT install budgie-remix-desktop nor budgie-desktop-environment as it will turn the whole Ubuntu system around.

Enable sloppy focus,

gsettings set org.gnome.desktop.wm.preferences focus-mode 'sloppy'
gsettings set org.gnome.desktop.wm.preferences raise-on-click true

Ref. https://askubuntu.com/questions/64605/how-do-i-set-focus-follows-mouse

Do not forget to enable workspaces,

Super-A
Configure
Top Panel // Add applet: Workspace Switcher

eventually change the menu icon,

Super-A
Configure
Top Panel // Budgie Menu
Menu Icon /usr/share/icons/ubuntu-mono-dark/actions/24/package-supported.svg

and of course the appropriate keyboard shortcuts e.g.,

Settings -> Keyboard
Navigation // Move to workspace 1 ... Super+1
Navigation // Switch to workspace 1 ... Alt+1
Windows // Close window ... Alt+Q
Windows // Maximize window ... Alt+`
Windows // View split on left ... Alt+Left
Windows // View split on right ... Alt+Right

if you need 4+ workspaces,

#dconf read /org/gnome/desktop/wm/keybindings/switch-to-workspace-1
dconf write /org/gnome/desktop/wm/keybindings/switch-to-workspace-5 "['<Alt>5']"
dconf write /org/gnome/desktop/wm/keybindings/switch-to-workspace-6 "['<Alt>6']"

ref. https://askubuntu.com/questions/332264/13-04-more-than-four-workspace-shortcuts-in-gnome-flashback-no-effects

enable alt-right-click to resize windows,

sudo apt install gnome-tweak-tool

Start -> Tweaks

Windows // Resize with Secondary-Click: (enable)
Windows // Windows Action Key: Alt

#(obsolete)
#sudo apt install compizconfig-settings-manager
#ccsm
#window management > resize window button2->button3

To launch Budgie from multi-user target (init 3),

vi ~/.xinitrc

#!/bin/bash

export XDG_CURRENT_DESKTOP=Budgie:GNOME
exec budgie-desktop

Ref. https://wiki.archlinux.org/index.php/Budgie_Desktop