If you don't like OSX, you can buy a MacBook Pro and run Windows. Or buy a comparable Windows notebook. The "who is it for?" question still stands. Casual users don't need many of the Surface's features, pro users need a "real" notebook.
I can answer coming from a user of a surface pro line.
its' a great go between hybrid device. Want to type something up? do some sysadmin work and need a keyboard? need full access to real software (and not just apps), from a library of millions of windows programs. you can. Plop it on the desk, snap it into the keyboard and work.
but then hey, I'm tired of working, i want to go watch sports and have my favourite sports blog up and website tracking my hockey poop. Pick it up, detach keyboard, and go sit on the couch. Full access to web, apps and still the millions of windows programs should I choose.
This is all being done on the same physical hardware. There's no need for some software layer like continuinity to link my mobile device to computer. There's no need for cloud storage to make sure that the photo i was looking at while at the desk, is the same i'm looking at while at the couch. No need to shut down programs from one computer, just to start them again on another.
it is one device to cover all of these activities fairly seamlessly.
Now, this isn't to say there aren't some caveats. it's not perfect. its heavier than an ipad. The trackpad is terrible compared to a laptop. The hinge isn't always the most practical of use.
but what it has allowed me to do is have on device instead of two independent ones.
if this doesn't sound like it suits your needs, then this device is absolutely not for you. But for many it might just be enough. I quite enjoy being able to sit on the couch and use lightroom with a competent touchscreen and a accurate stylus.