I decided to try out Duet Display for the first time this weekend (based on a post from MacSparky). I’m impressed with it. I really like that it uses a Thunderbolt connection so doesn’t require WiFi or something else I wouldn’t trust. With the iPad Pro it gives you a lot of space. When I’m traveling and want to setup for some serious work being able to set the iPad Pro up as a 2nd display will be great.
Definitely work checking out if you have an iPad Pro or even iPad.