As a user I've long been a tablet fan, I own several iPads and Surface tablets that are still actively used in our family. Until recently I used a Surface Pro 1 for work, I'm now getting a shiny new and fully loaded Surface Pro 4.
Using a Surface tablet as a PC (with monitor and keyboard and mouse attached) works very well, as many people have found. But Surface never really competed with iPad as a tablet, purely using touch. I know nobody who uses and likes Metro IE, Windows Mail, reads the newspaper using an app or plays games on it.
Except me: I've always felt that the only thing lacking on the Surface to compete as a tablet is good Apps and users willing to invest time learning to use it. People would find it actually is quite nice. Even the doomed Surface RT2 is superior to an iPad for many tasks, once you "get" Metro IE, the keyboard and multitasking gestures. I regularly write comments here on HN using Surface in tablet mode, which is much less fun when I try it on an iPad.
When Surface really succeeds in the market, my hope is that the App platform will finally start working. As a developer, the technology and tools feel vastly superior and more productive that those of Android and iOS so I'd be happy to start developing Windows-first again.