Pocketsphinx is going to win on mobile platforms. Right now there is no alternative to using it because of performance, accuracy and flexibility. Using pretrained US English acoustic models one can get amazing results.
That was proved once again by amazing Nightingale Browser Project. Check this video how it works
If you like it, feel free to contribute to the project. Checkout source from Gitorious http://gitorious.org/nightingale, clone, send patches, report bugs!
And, to not make you confused. Pocketsphinx is not only for mobile. You can perfectly use it in desktop applications, even in large scalable application. It’s accuracy is the best we can suggest you right now!