This is weird. Phillips has the UE900 rated
"101.2 dB @ 1 kHz, 50mW" for sensitivity. Usually that rating is at 1mW. Are they supposed to be hard to drive? Not usually the case for IEMs. Probably just a mistake in the specification, in which case, any of the regularly recommended portable amps on Head-Fi would be able to drive them to very loud volumes.
I had the Note 2. The DAC in it was pretty good. I did use my my E12 with it on occasion. But unless the headphones needed the extra volume, a lot of times I didn't bother. Just was a hassle to me to hook up the E12 and use it.
Are you listening to music files with your phone? If so, you might consider the Fiio X3. It's the same dac/amp as in the Fiio E17, only a bit better optimized. Then you don't have two devices hooked together to be able to listen to your music, and you don't have to worry about running down your phone battery