I got the SP4 (i5 / 128GB) last week because you couldn't get the Apple Pencil from anywhere. I'm planning to use it for a few weeks and then decide if I'll keep it or get the iPad Pro + Pencil.
I haven't done any extensive work yet, most of my time has went to configuring the thing to suit my workflow. I'm planning to post more impressions later.
After 5 days, I think SP4 (for art) is pretty good. There are pros and cons. Hardware is pretty amazing and W10 enables so many possibilities. Firmware / OS has bugs, but I'm not concerned about those, they will be ironed out sooner or later.
The pen isn't as good as my Wacom or the iPad Pro I tried, it's not nearly as sensitive (initial activation force) which makes it feel a bit janky and then there's the famous jitter problem. But I draw fast lines so the jitter does not concern me personally, and I'm getting used to the pressure issue. I just don't have as much line control as on my Intuos.
Then there's the software side. I've tried maybe a dozen different applications and sadly none of them come close to Procreate in UI touch experience AND functionality / line quality. One of those has always lacked.
And if I whip out a BT keyboard to the side so I can use all my Photoshop / Painter hotkeys, it's not that ultramobile sketchbook anymore.
But if you're a technical person and don't mind the configuration hell, you can get around that problem. You got options like the touchscreen hotkeys (or that BT keyboard, if it's okay for you).
You can also use autohotkey to remap the eraser button of the SP4 pen. Frankly, the other "button" is a useless piece of crap, it's just disgusting to press, very stiff and low profile.
But you can add 3 functions to the eraser button (one press, press twice and hold), it's nice.
Or you can get creative and attach some cool, very small bluetooth gadget with just a few buttons to handle your usual hotkeys.
I have the type cover for SP4, but I think it's useless for drawing because of the ergonomics. If you could use it separately via BT on the side, it would be better. But it's a nice cover and keyboard when you do a lot of typing.
Here's my Photoshop workspace, and a very quick doodle I did just now.
I'm using this Japanese software called
TouchKey which looks crappy compared to something software like Procreate has, but it's functional and reliable. Like Japanese cars. You can see the toolbar I built on the left.
I tried also other similiar programs but they didn't feel as reliable to me. With this I can create toolbars for every app I use, they load automatically when I switch programs, and they are solid.
Overall, right now I'm pretty happy with my SP4. It has some things it could do better, and there's a lot of things the app developers (Adobe, Corel) could do better to support the W10 tablet experience.
But because it's Windows I could hack my way through most problems I've had, thanks to limitless customization options via 3rd party software.