Been down that route......
Reading the comments, I have been down the small form factor route.
The use case being carrying our online life with us when travelling round the world.
Firstly an eePC running Linux, which then had XP added.
Retired when "upgrades" to XP ate all the SSD space and I couldn't be added to wipe it and start from scratch. Because I was back home with my full fat PCs.
Next long trip I got a Sony Xperia Z tablet with USB keyboard and mouse. Worked OK (still have it) but not really as good as Windows for support of various 3rd party hardware such as SatNav. It also needs the USB port replacing and no TUIT has been sufficiently round so far. I knew there was a reason that I bought the optional charging station that used the two external contacts. I hadn't realised that it covered the USB port so couldn't be used as a docking station but it came good in the end.
Recently I bought a Dell Latitude off fleabay. Dirt cheap with the low res (described as HD) screen) but harder to find and more expensive with the full HD screen. Which is as high a resolution as you need for an 11" screen IMHO. Well, I bought two in the end. An i5 without Thunderbolt and an i7 with Thunderbolt. Roughly £250 and £325 respectively but I couldn't be added to wait for a better deal.
Given that my old Core 2 Duo Dell XPS (must be 10 years plus now) which originally came with Vista is still rocking W8 like a train I expect the Latitudes to last another 5-10 years, unlike the cheap and cheerful HP W8 netbook-alike which didn't survive a couple of drop tests. Umm...missed that out of the list of global travelling items. See icon.
Which finally brings me to the point. I have a number of Pis but have never used them as a desktop because I have always had more powerful PCs at home.
For portable use I can't see anything obvious this setup can do which can't be done better by a "proper" laptop.
So I am with the reviewer there.
This seems to be for people with enough money to afford to buy an empty laptop casing and then plug in something external just to be different. Happy for them. It is not for me.
I am, though, wondering if there is enough functionality in the CI slot found on UK TVs to take a CAM which could support some variant of a Pi. You could then carry a small card and a wireless keyboard and plug into any TV to have a fully functioning PC. Assuming Internet connection, of course. That might be of interest to a road warrior or someone with TVs in the kids rooms. Doesn't enable working on the train, though. Unlikely to be crowd funded in the USA unless they have CI slots in TVs as well.