My Surface replaced my laptop, and while I definitely had my issues with the transition (trackpad sucks so often use external mouse, aspect ratio is inconvenient for Office, display angle is limiting, and no built-in LTE), I've ultimately come to enjoy using it.
I've almost always got it with me, and I've found I've become nearly as productive on it as I was with my laptop. I've been willing to make the "nearly" tradeoff since I have it on me more often, so more opportunity to be productive, and I do use it as a tablet in ways that I obviously couldn't with my laptop.
The updates in the Gen 3 address nearly all of my gripes (why can't they integrate LTE??). I'm not sure if I'll pick up a 3, but only because my Gen 1 is less than 2 years old and still under warranty. If not a Gen 3, then a Gen 4 will definitely be on my shopping list.
I can't imagine I'll go back to a normal laptop. I guess I'm exactly who they are targeting.