Yes, there is a HUGE difference between the Surface and the Surface Pro line. And there is also a huge jump in the first three generations of the Surface Pro line. I have a Pro 3 at home and a Pro 4 at work. The Pro 3 is decent for casual use. A mid-level or high end Surface Pro 4 can replace your home computer for most things (just hook up an external monitor or two, a mouse & keyboard, and you're good to go). And the keyboard-cover and pen for the Pro 4 are vastly better than the Pro 3 units.

The Surface Book is Microsoft's answer to the MacBook Pro and iPad Pro all in a "single" device. I don't totally get it myself; but my MacBook Pro is getting old so we'll see what I buy next. Haven't been as impressed with Apple in the last 2-3 years as I was durIng their tremendous run from 2006-2014.

--Noel