Firefox OS: Go away fanbois, fandroids - you wouldn't understand
Repeat after me: developers, developers, developers, developers...
The web-developer angle is self evident
Using familiar web tools doesn't just mean more developers to build apps, it also allows Firefox OS to avoid the sort of device fragmentation that currently plagues Android.
As Mozilla developer evangelist Christian Heilmann emphasised when I spoke to him about Firefox OS: "You don't build to the hardware, you build to HTML5."
How much hardware access your app receives depends on what sort of app it is. There are three different types of apps: web apps, which don't have access to lower-level APIs; privileged apps, which have access to more sensitive APIs and must be approved by Mozilla; and certified apps, which are limited to those from Mozilla and partners.
However different Mozilla's approach may be at the operating system and developer levels, many aspects of Firefox OS will have app developers feeling right at home - like the Firefox Marketplace app store, which offers the same sort of benefits found in the iOS App Store or Google Play. That is, your customers have access to a dead simple payment system for apps that need it (billing is handled by the carrier), apps are vetted and updates are automatic.
There's one big difference though between Mozilla's App Store and the app stores you're used to: developers aren't compelled to use it. Developers can distribute apps through the store, through their own websites or through any other store build with Mozilla's open-source tools.
Despite the fact that the Keon is aimed at developers it's impossible to use it for any length of time without forming some opinions from a user point of view. While the hardware is uninspiring it never failed me. I dropped in a SIM card and had no trouble making calls, using location-based apps or any of the other features key to mobile apps, including camera, microphone, accelerometer and so on.
Calls were crisp and no one I talk to on a regular basis noticed any difference from the Samsung Nexus I normally use. The battery managed to just barely meet its claim of "all-day", though this definitely isn't a phone you can forget to charge for a few days. The rubberised back is comfortable in your hand and does a nice job of padding against the accidental drop. The camera takes mediocre photos compared to high-end phones, but again that's to be expected in a budget phone aimed at developers.
But if the Keon isn't the best hardware around, well, that's part of the plan. Mozilla's first developer phone has low-end hardware in part so developers can afford it, but the auxiliary benefit is that it forces developers to build apps which run smoothly on underpowered hardware (meaning they'll run even better on more powerful consumer devices).
To answer the question you're already thinking: no, Mozilla doesn't plan to support Firefox OS as an operating system you install on any phone. That doesn't mean you can't hack Firefox OS onto a phone. I managed it on a Nexus 4, others have had success with Sony devices and Firefox OS has turned up on Raspberry Pis.
The problem is that to create that bridge between web app and hardware, Firefox OS needs to talk to device drivers and very few phone manufacturers offer up the inner workings of their drivers. In short, it's possible to install Firefox OS on other devices, but it's not something Mozilla currently supports – and nor is it likely to need to.
Mozilla has already lined up hardware and carrier partnerships around the world, including the US which is home ground for the iPhone-Android duopoly and where Sprint is now working to bring some sort of Firefox OS phone to the market.
Ironically, Mozilla's open web-based vision for mobile devices dovetails with the less open vision Apple’s co-founder and former chief executive Steve Jobs outlined for the iPhone. Jobs gave up on the idea of open, but Heilmann acknowledged there is overlap. "Apple has talked up HTML5," he says "but it doesn't offer the hardware access developers need to actually build HTML5 apps." Firefox OS does offer that access and Mozilla hopes that will help Firefox OS gain a foothold where many have already failed.
At least that's the idea. After using the Keon for a month I can say I hope that Mozilla's model succeeds because it simplifies things, both for developers and consumers.
Developers could win because the web offers the best hope yet for creating the fabled build-once and run-everywhere world. Consumers could win because it lower barriers to entry, which means more developers participate, and that in turn that means there are more cool apps to try.
Even if Firefox OS isn't the vehicle that wins this race, it seems unlikely that whichever mobile OS does will be all that different from the desktop. Thus far, it seems that old maxim is right: the web always wins in the end. ®