I bought a 7" Amazon Kindle Fire HD for Christmas, and I know how good the high resolution screens are, its only 7 inches, but I can read text with no problem. However, I need a keyboard. I use a pen with the Amazon tablet, the same pen works with my G1X MK II, but I struggle swiping with pens because the fine motor function in my fingers is screwed up. I can pound keys, and tap the keys on screen with the pen, but even writing my name has become extremely difficult. I have a Wacom Tablet, but that issue using the pen really makes it hard to use. Its not something that practice is going to eliminate, the nerves are shot. I've already had surgery on both hands, but that did not really help.
I had looked the Surface Pro II over before getting the cheap tablet, its useful for e-mail and reading books, that's all I use it for though. I'd probably use the Surface Pro.
The Pro 3 is a bit larger, and I think by default it comes with the attachable keyboard that has real keys. In the store, it felt very nice. The kickstand has been dramatically improved as well. It now works at pretty much any angle, and can even be pushed far out such that you can actually use the whole setup on your lap (like a normal laptop). The screen lays out more flat, over your knees, but it actually can work, where as with the prior Surface Pros, using them in your lap was pretty tough. I got the touch keypad with my Surface Pro...and that is the only thing I really regret. The type keypad is much better, the standard keyboard feedback is just essential, imo, to be able to use the keyboard properly.
Regarding the pen...it's incredibly natural. You don't have to do any special moves or anything like that to get it to work. It isn't the same as a Wacom tablet, those are devices intended to control palettes of controls, use gestures for controlling application features, etc. They are much more complicated, and these days, maybe needlessly so. With the Surface Pen, you bring it close to the screen (don't even have to touch it), and you get a small round cursor, kind of like the mouse cursor. That cursor will lightly and intelligently "snap" to controls, so it's pretty easy to get it onto buttons and things like that...it was pretty effortless to get it onto the LR develop module sliders, which on my Surface Pro I, are really tiny. From there on out, you can effectively use the pen like a mouse. You can seamlessly move between using the pen as a mouse, to using it to tap keys on a virtual keyboard, to using it for handwriting input (which also works flawlessly, I take notes in business meetings on my Surface Pro with the handwriting feature...it's amazing, it worked from day one without any training of any kind, printed or cursive.) It's pressure sensitive, so it can be used for art or just general brushing in photoshop (i.e. dodge/burn), it has an eraser for word deletion in documents or when handwriting. There are also other pens and digital brushes you can get that work with the Pro 3 as well, although from what I've read, most of those are really geared towards the digital artist, people who are literally painting digitally in some of the new metro apps designed just for that thing.
At the very least, I recommend going into a Microsoft store and just giving the whole package a try. It's best to know what your getting before you get it, and you may simply find something about the design and style of the Surface Pro just doesn't fit your usage scenario (it fills a rather unique spot, being kind of the ultimate convertible tablet, that really works like a laptop, but is also a true tablet.) You may find that one of the other brands convertibles is better (i.e. you may just not be able to use the Surface Pro 3 on your lap, and need a more rigid and more rigidly attached keyboard). I would be willing to bet, though, that you pick up the pen pretty quickly. It's kind of an essential tool, as not every app supports high DPI modes yet, and some older ones render controls pretty small on high DPI screens.