I'm very "disappointented" by the event, as it seems that the Surface Book series is dead.
If this is the case, I guess that the reasoning has been that who want a powerful machine just buy a regular laptop.
It's a shame for those who use the SB both as tablet and dev machine (which is the intended audience). At this point, it's not sure how the SPX will be usable as dev machine (e.g. I guess it will have relatively little memory). The vanilla SP is an alternative, but 12.3" is small for me (and can't imagine for those who own a 15" SB).
I know a load of people with the standard Surface that use it like a tablet, but very few people that regularly use their Surface Book's detachable tablet functionality. I can probably count the number of times I've ever wanted to take the laptop apart on one hand.
In the past, I used it primarily to read electronic versions of several paper magazines; this format is (IMHO) best read on a large screen - the sweet spot is around 14, so 13.5 is the closest (I reckon the 15" is too big; the SB laptop form factor has a bulky design).
In the present, I use it for studying (textbooks, mostly) - for textbooks, even 12.x" is fine, so even a Surface Pro would do.
Having said that, I like it as a tablet so much that I've pretty much ditched the base and bought another laptop for development. The SB laptop form factor just sucks (IMHO), as it's very bulky, and Microsoft has an insane pricing strategy, that makes it unjustifiably expensive for developers looking for a serious dev machine. Nowadays it's more competitive due to being old, but the 16 GB models have never been competitive, both in price and form factor, to competitors like the Dell XPS.
Of course, I don't imply that many people use it this way because I do, so I really don't know the general use cases :-)
