I'm constantly on the lookout for the elusive "ultimate" ultraportable. There are so many choices these days it's insane. Ideally I'd want something super light, new/powerful processor, long battery life, able to play some games (Diablo 3 minimum), doesn't get too hot in your lap, big/nice screen (touch optional but nice), good keyboard and touchpad, backlit keyboard, decent RAM and SSD speed/size, "instant" on...
Depending on priorities, there are some great and interesting options out there. The Dell XPS 13 is really attractive. I had an early version and it's only getting better with time. It meets almost all my criteria with a 13.3" screen at just about 3 pounds and the battery life is fantastic. There are a number of 2-in-1s that come close feature-wise, including the Microsoft Surface series. I've been using the Surface Book which seemed like it was going to be more or less the best of both worlds, but in practice it falls short for me in a key usage scenario. Like other transformer types I think the core circuitry is all held in the tablet unit, but for whatever reason that messes up the return from sleep/off time, especially if not plugged in. If it runs out of battery, even plugged in I often couldn't get it back up and running quickly. For something like this I want to be able to hit the power button (or better yet open the screen like a Mac) and just get back to it. Very frustrating because I like most of the rest of the design choices. Speaking of Mac, the recent Macbook (12" at 2 pounds) pretty much fits all my criteria as well, but the negative was the battery life wasn't meeting my expectations, and the screen size felt a little small. Also the USB-C single port is/was kind of annoying, especially since it's used for power as well.
I wasn't necessarily looking for a replacement, but I was at Fry's the other day and happened on the above-mentioned LG unit. As I walked around looking at the laptops, I would pick them up while checking out their screens. This one when I picked it up I thought it was a fake/shell because the screen wasn't on initially and it felt too light to be a real laptop (especially at 15"). The difference between a 2 pounder and 3 pounder is really incredible. Is it really helpful or necessary? YMMV, but there's no denying it's a different experience carrying around. The LG is by no means perfect. The keyboard is just OK and the touchpad is really lacking compared to a Macbook Air. But a 15" 1080p screen at this weight is absolutely insane, particularly running with the latest i5/i7 processor. I haven't done much with it yet but I really do marvel at the weight, and so far it's been good at getting me back to my desktop quickly. I suspect the battery life is going to be disappointing, and there's no backlight on the keyboard, which is a bit annoying for me.
Ultimately I don't know if such a design/featureset is really useful for most people. I guess it depends on specific needs/desires. Maybe nice for college students on the run a lot who really want the lightest weight but also prefer a larger screen? If you happen to come across it, though, I do recommend lifting it up just to get the feel of it, it's definitely very different from the vast majority of ultraportables.