Can echo what other have said. I've been pretty much on a completely Apple ecosystem the last 12 years or so. First machines were OS9, and have been moving up right through Mavericks and the latest iOS. TiBooks, AiBooks, PowerBooks, G5, MBP, rMBP, iPads, iPhones, AppleTVs, Airport Extreme, etc...
I've been waiting for Apple to breed the MBAir and iPad, but it just hasn't happened. As an associate professor, I really need to be able to make annotations on slides live during lectures, and it just wasn't happening in the Apple world. My rMBP wouldn't even play nice with a SMART Podium (with it's own digital inking capabilities) while running PowerPoint 2011, and Keynote was out of the question (I was told by the SMART techs that Keynote doesn't let anything else sit "on top" of the presentations, so they haven't been able to make their classroom tech work with Keynote). I've heard reference that the Mac version of Office are a generation behind the Window's versions, but I think it's generations behind. Office 2013/365 is fantastic for my workflow -- Mac Office 2011 is completely second/third rate compared to it (I realize this isn't Apple's responsibility, but MS's...; however, as much as Keynote has going for it, the lack of digital inking capability is a show-stopper).
So I took the plunge with the SP3. It's been a bit of a learning curve, but I *am* loving it. It's tough to define my workflow: I'm back and forth and in and out of the desktop and MUI apps constantly. Sometimes I swipe; sometimes I right click on the Arc... Sometime I'm in MUI; sometimes in desktop. Sometimes I touch, sometimes I use the track pad or mouse click. That's the awesome beauty of this machine -- the best of both worlds are literally at your fingertips. The Start screen tiles took a little getting used to and at first I stayed in desktop mode, but now that I've gotten a feel for it and have made it "my own", I'm rarely on the desktop -- loving the tiles... The main MUI apps I'm using are Tapatalk (wishing for Tapatalk HD, but this suffices...), IE (the MUI version is scaled wonderfully for touch mode), Bing Weather, AP for news, occasionally checking in on FB, WSJ, etc. Getting used to Mail and Calendar as well -- seem to work nice for quick e-mail & schedule checks. [At first I was missing some of the apps like the ones my banks put out for iPad, but the MUI version of IE is scaled and performs so nicely, I just go to their sites -- I've found I don't *need* a lot of the special apps that I seemed to need on the iPad....]
Bottom line: iPad rarely gets turned on anymore, and the rMBP only gets turned on for convenience and photography (LR) work. The convenience part is because it's hooked up to a 27" NEC monitor plus a nice Mac keyboard, touchpad and Wacom tablet; once my SP3 docking station comes in I suspect the rMBP will only be turned on when I want to work on photo editing...
I'm not sure I would have gotten to this place just playing with the SP3 in a store for a half hour though -- it's taken a few weeks for things to really start to click (and I have much more to learn).