Yeah, it took a bit, but I've finally got it running well. As you can tell from my posts above, I'm not too patient of a person, but now that it's moving on full steam ahead, I love it. About the only thing that'll make me take it back now will be MS introducing the Surface 4 this coming Tuesday.
As for Win8 vs. Win10, I'll admit that I don't have much hands on time with 8 on a tablet, but 10 in tablet mode works perfectly well for me. I could see someone missing the Charms Bar, but the action center does roughly the same thing, just not as thumb friendly. Task View I think is better than swishing through apps one at a time. An Expose like setup is something I've always wanted on my iPad, and now that I have it here, I can multitask like a mofo. I have no complaints as far as base usability goes.
The only thing I wish is that all the icons in the notification area would show up in tablet mode. It kinda sucks having to jump back to the desktop to kill off apps that go nesting there when you close them.
My biggest gripe so far is what a complete piece of crap the Edge browser is in win10. Modern IE in win8 was so much superior in every aspect. Once MS fixes Edge to have swipe gestures, be able to go full screen and have extensions then I'll accept the other deficiencies in tablet functionality and switch over. I've installed win10 onto my surface pro 3 about 4 times now, forcing myself to accept it. I usually give up after a week or so and uninstall it in disgust.
Charms bar was awesome. I'm just so utterly confused why MS would nix something as useful as the brightness and volume slider. Also just plain obvious stuff, like having time, battery life, WiFi signal, etc when swiping the charms bar. Task view isn't my cup of tea, but it's ok and I can get used to it. But I can get used to all that stuff even if I hate it, but I cannot ever give up my Modern IE.
I do have win10 on my home and work desktop, it's a great OS for desktop use. But don't get me wrong, even win10 trounces all over iOS in a big way. I highly suggest you pick up a dock, they are routinely on sale for $100 or so, it's an awesome feeling just plopping the surface into a dock and having a full computer, mouse, keyboard, big monitor, external storage, etc. My SP3 is my main PC at work, but when I need to I can pop it out of the dock if I need to show studies or anything to a patient.