The concept is fairly simple, but a lot harder to execute due to many factors such as size, design, compatibility, convincing companies to start making products for such a concept etc.
While Steve Job's believe is that if you want to make something good, you do everything in house from the UI to the design, Ara goes around the other route, putting the design and specs in the hands of third party manufacturers (eventually) to produce different types of components. While I agree with Steve seeing how Apple has become so successful following this mantra, it's interesting to see if Ara will be able to break the mold once again...and since this is targeting at a much lower end market as well, it already looks a lot more decent than the half past six products you get out there in the low end smartphone range. At the current design stage though I can't say I'm liking what I see, but it's definitely better than what...a Galaxy Ace?
Cool stuff, let's see what the ex-DARPA team can come up with in the next 365 days.