I have an N910G (Australian version). We finally got our OTA update a couple of days ago, and I'd been waiting excitedly for it since Lollipop was supposed to add native sample-rate output support. With 4.4, my Note 4 worked over USB with my desktop DAC (Yulong DA8), but only at the fixed 48KHz output pre-Lollipop Android allowed. It really didn't sound very good, strangely hollow and with random clicks and pops that wouldn't repeat if you rewound the track and played it again. I don't know if this was the fault of the enforced sample rate conversion and/or the quality with which it was being done, or a problem of some sort with my particular unit, or what, but I was looking forward to Lollipop narrowing things down for me.
Welp, after updating, USB audio doesn't work at all. The DAC and phone both behave like they aren't plugged into each other, neither seems to notice the other. I really wanted to plug it in and see that "44KHz" come up showing my music was finally escaping unmolested, so it was a real let down to see nothing happen at all. Now, this apparently works fine with Nexus devices running 5.0.x, so it seems Samsung has to have specifically removed or disabled this feature in their implementation of Lollipop. What, Samsung? Why give us a feature in the shipping phone, then turn it off at random? Especially when many competitors have it working, and leaving it in place doesn't cost you anything? (And surely removing it must have? So why?)
I'm not sure if the above will affect your decision to upgrade to 5.0.1, but I certainly wish I'd known beforehand.