It works. I've been using it on the Galaxy S3, dual-core. The phone's wifi hotspot software starts along with FoxFi in the form of a notification, which is annoying, but if you ignore it then it's not an issue. Only thing is, I've noticed it takes my laptop or PC forever to "identify" the network, and I sometimes, for some strange reason, have a windows IP address conflict. I've renewed the IP on the PC end, to no avail. Because of this, I occasionally have to restart my phone to set up a working hotspot (very rarely). I haven't looked too far into whether it's been an ongoing problem on my PC or just FoxFi on JB's, but it wasn't happening before the JB update. As of right now, I'm on my self-built home PC and it's working great. In fact, I cancelled Comcast because the speed tests I ran under-performed my phone's outrageous 4G speed. I also use my PS3 to connect to my phone wirelessly where I am able to stream HD Netflix content.
My opinion, there MIGHT be something a tad bit janky about FoxFi on JB, as it seems to have worked without ANY hitches on ICS.. it DOES work fine now but I've noticed a few hindrances and hiccups, unknown to me whether a PC or FoxFi issue. The software update itself, with Google Now, fluidity tweaks, new features and stability are definitely worth the update.
So, in the end, I encourage you to update your damn phone!
- - - Updated - - -
Oh, and MERRY CHRISTMAS!!!