In early 2011, I bought an Asus See Slate EP121 from Best Buy Canada. Microsoft had specifically marketed it as the tablet-laptop hybrid of the future (which seems just cruel in hindsight seeing as they were working on the Surface Pro at the same time), but it seemed well-priced and I had a grad thesis to write. I got Best Buy's extended protection plan, and they gave me 3 years for the price of 2 as an apology for having to exchange the first couple of (defective) units.
In the third year, I waited until Best Buy Canada was completely out of stock on the Asus Eee Slate and then brought in the device for replacement, due to a number of hardware issues (screen discolouration, cracked plastic casing). Their policy is that if they can't repair, they'll either replace the device with a new one or, if the same device is not available, provide the customer with the closest match. So I got the Surface Pro (version 1) for free in 2013, but then bought a touch cover and a new protection plan. I recently sold it on Craigslist for $300, breaking even on those extras...
I've watched the Surface line get better and better, but have held out for Skylake processors. The Surface Book is actually about the same weight and thickness as my old Surface Pro (v.1) with type cover attached, and between the EP121 and the SP1 I've been able to figure out where I land on the typing-tableting spectrum (closer to the former). I would have been completely happy with the SP4, but the SB was too cool to pass up.
Hopefully this lasts until the Surface Book 4 is released in 2019 (but by then I'll probably go HoloLens), lol