Yes, using a Samsung 128GB microSD formatted as Internal (Adopted) Storage. My device is the xt1548 Sprint compatible Osprey. I have experienced no problems, bugs, instabilities, etc.
That's a good question. I'm really not sure, but if it helps any, mine is a UHS-I Samsung 128GB EVO Standard micro SDXC (Class 10) card.
/* * Your warranty is now void. * * I am not responsible for bricked devices, dead SD cards, * thermonuclear war, or you getting fired because the alarm app failed. Please * do some research if you have any concerns about features included in this ROM * before flashing it! YOU are choosing to make these modifications, and if * you point the finger at me for messing up your device, I will laugh at you. */