I love the look of the new MacBook. To me it feels like an iPad for people who want a keyboard and desktop class apps: Super thin and light with sufficent power.
If your needs are mainstream it's a brilliant machine. You can easily do browsing, email, office apps, social media, some photo editing, watching Netflix and YouTube, and so on. It's insanely thin and light, meaning it's a great machine for those who travel a lot.
If you use a camera for videoing sessions, there is no manual way to transfer the photos and videos to the MacBook yet. No SD port, no adaptor. Wifi transfer would fix this of course.
As most of this can also be applied to the iPad, it goes to show you don't need both devices, and it become a matter of personal requirement.
If you need expandability, you probably wouldn't want either an iPad or the new MacBook, but there are other options. So, if that's not a deal breaker, it's down to whether iOS or OSX has the best apps for your particular needs.
I'd argue most of the time the iPad is a better choice, especially as a travel computer. Unless you specifically need OSX.
I could certainly find a use for it in my setup, especially when third-party expansion comes out. My work CMS is designed for desktop browsers, I have never been brave enough to podcast from it and I run a couple of apps that don't work on the iPad. That said, i could do that with any modern laptop, so I can't justify the trade-off in power that the lightness brings.
Its certainly appealing to look at, and I know my girlfriend would love a gold one, but for now I'll stick with the iPad and my work Dell Ultrabook.