Sencha touch has lived longer than jquerymobile but I found that jquerymobile handles device back button much better than SenchaTouch.
I always consider back/history button handling is important in my apps, so I prefer jquerymobile.
I always consider myself a JavaScript programmer, but I like the fact that I rarely need to to type any JavaScript code when I use jquerymobile.
jquerymobile design is brilliant IMHO.
