Stephen Shankland/CNET

BARCELONA, Spain -- An iPhone fanboy will sneer at it. A long-term Android user will have unpleasant flashbacks to the early versions of Google's operating system.

But Mozilla's $25 Firefox OS smartphone is real.

I toyed with a prototype Sunday at its debut at Mobile World Congress here, and I have to say, I'm impressed -- given the price.

It's missing things like WhatsApp, its screen is small and coarse, and it's slower to scroll and launch apps than the state-of-the-art phones from the last decade. It's not something a rich kid from New Jersey or a businessman from Tokyo would be caught dead with.

That's not the target market. As any number of bruised companies can attest, taking on Android and iOS head on is difficult, but Firefox OS today is geared for a much more cost-sensitive market. Mozilla, reasonably, tells those who would judge this Firefox OS model that they should compare it to a bargain-bin feature phone with a few built-in apps and a low-end camera.

"Imagine that phone in your pocket is a feature phone. Imagine when you go buy one of these devices that every euro is precious to you," Mozilla leader Mitchell Baker said at a press conference here. Looking at "the richness and power we're able to offer to this market, you'll be astonished," he said.

And for that market, it really works. You can install apps, load Web pages, search your contacts, and send e-mail typed with an on-screen keyboard. You can multitask and play music in the background. You can un-pinch to zoom into photos. The Spreadtrum chip that makes it all possible only works on 2.5G Edge networks, so it's slow, but in third-world countries, that's often the network that's available.

Even if Firefox OS gains a strong foothold in lower-end phones, Mozilla will face longer-term challenges as cheaper hardware brings Android down-market. Firefox OS today works in a quarter the memory that Android now requires, though, and that could mean the difference between profit and not for a super-low-end smartphone.

So no, I'm not going to recommend this phone to my relatively affluent friends. But for the price of a nice bottle of wine, it's an impressive achievement.