If I made another dashboard today, I'd do it with UI - even though @jumblerg encourages people not to use it
On the other hand, "nobody ever got fired for using Bootstrap". So, I think it depends on your enthusiasm for learning UI.
Personally, I'm extremely enthusiastic about UI. I haven't used it myself but I was fortunate to get a demo, and I'm convinced anything you build with it will be simpler than anything you could build atop Bootstrap, even considering the UI API is likely to change more before @jumblerg finally encourages us to use it.