Thank you so much for your response. About the volume issues you mention, it's kinda funny, but I think the G4 sounds loud enough. It might be of course due to my own tastes - I don't like ear-piercing volume on my music. So there you have it. Other than the volume output, how did you find the G4 music capabilities? Did you enjoy the sound signature? Do you think it was good at hi-res audio? Which headphone and IEM's did you try on it?
At some point I intended to get the Meizu X4 Pro, just like you, but no carrier in my country sells it, and importing it is too costly, so it was out of the question. Also, since my contract had just expired, I could get any flagship at a big discount by renewing my contract, so then again, buying the X4 Pro on my own did not have the benefits and discounts of getting my phone from my mobile carrier. Thus, my Z3 vs M9 personal debate that met a last minute turn when I saw the G4.
I know thay there are better phones than this one (the X4 Pro, Z3 and M8/9 for music, iPhone 6 and Galaxy S6 for the camera, and the S6 and X4 Pro for hardware performance), but as an all-rounder, I personally think no other phone can beat the G4, and I'm really happy for it.