I agree: the site accomplished its only stated goal. As someone who was approached by usesthis to be on their site (just last week: I have not said "no" yet) I can say that the guy who runs it specifically seems to have not cared much about how to optimize for generating insight into the /why/ behind what people are using.
Personally, however, I found that quite disappointing. :( Reading through the list of people and what they had to say I'm thinking, "man, I wonder if that was a random choice, or something that person spent a lot of time thinking about". Maybe I'm weird, but just knowing that someone who's work I admire has a Compaq Concerto isn't interesting if I don't understand the tradeoffs that went into its purchase.
Another complaint I have is that the site attempts what I believe to be a strong and artificial separation between hardware and software, and even requires a fixed ordering: hardware first, software second.
In my experience, software and hardware are really two different physical manifestations of the same underlying concepts (maybe I've spent way too much time on projects that involved writing software to accomplish the same goal as a previous generation's fixed function hardware), and end up having dependency relationships that criss-cross the supposed boundary.
As an example, many people interviewed on the site mentioned that they own a MacBook only because they were recently doing a lot of iPhone development and needed to use Apple's iOS SDK. However, it led to awkward phrasing to do that in the hardware section (before they had a chance to go more in depth into the software later), so the comment is stilted at the top and then short changed later (as it was already mentioned earlier).
It is also quite common, however, for people to first look at physical device properties like form factor, screen size, or input subsystem, leading them to make decisions that sound like "once I decided I had to have a netbook, I started evaluating whether to run Debian or Windows 7: either would be fine as I really only needed to run Chrome and a terminal".
I therefore look at this website as a giant list of missed opportunities to learn something really interesting and important about a number of really awesome people, and while I again agree: the site accomplished its stated goal, I think it is appropriate to judge a site on whether the underlying concept was appropriate in addition to whether they succeeded at their implementation.