I respectfully disagree with the statement that MS has worked out the bugs. They have NOT. I used to use my SB in "tent mode" a lot, but stopped because my screen would just go black when I'd detach or re-attach it about 1/3 to half the time after the November update (this never happened prior to the November Windows 10 update). No rhyme or reason to it but I hated forcing it to reboot so often.
SB as a tablet is just OK when compared to a Surface Pro. The Pro 3 (and probably 4, but I don't know as I don't have a Pro 4) is a far, far better tablet experience than the Surface Book, IMHO. For one, Windows 8.1 is more stable as a tablet OS than 10 is currently. For another, the Pro has the built in kickstand for using the device as a tablet. The Book's keyboard base is grossly heavy if you're only using it as a stand and really don't need the laptop capabilities. If you want a tablet, get a Surface Pro and skip the book. If you need a laptop that can be a tablet sometimes, then the Surface Book is nice for that, provided you don't run into the same issue that I do with the black screen on detach/re-attach.
The main reason I went to a Surface Book from the Pro 3 was because I desperately wanted the GPU's power. Intel's integrated graphics are OK, but suck for heftier games & for hardcore graphics work. I completely miss the portability factor of the Surface Pro, but I adore the ability to sit on my couch & watch a baseball game while playing Diablo 3 at the same time, and when I'm done playing, be able to detach the screen and play casual games like Solitaire or surf the web with a lighter unit in my lap. There's just nothing else quite like it. When MS works out more of the bugs (and Intel fixes their drivers), the Surface Book will be a unique & fantastic 2-in-1, but IMHO, it is NOT the best "tablet" on the market by far.