[Lycosa777]

  if you're using the phone itself, htc. much newer, etc.
 
If you only use it as a music player, go for the 4s, or maybe better a standalone Hifi Player? like, Fiio X3, some Cowon or something like that.
since here you won't pay for 95% the features you won't use.
 
But in terms of audioquality, the M8 is a beast (don't have comparison to the iPhone 4s).
M8 has an output impedance of 1.2 ohm or so~, an Output voltage of 1.2 - 1.3 Volt, and in addition to that, a quite high output Power (in watt), depending on the impedance of the headphone.

Awesome phone but it does not live up to the hype. Speaker sound quality is phenomenal but headphone output its terrible. Detail, instrument separation, layers - Nothing. I used the SGS1 as a music player over the M8 for a long time and found it to sound great for a mobile device. But then compared to something as cheap as the Hifime U2, there is no comparison. The sound signature is fine, but I did not enjoy what I heard out of my M8.

 

[Karl2009]

I have seen that this phone can be found in the second market for less than $100.
I am thinking to buy and use it just as a player with BT and streaming ability.
Is the M8 hifi performance comparable to the Fiio X1 or X3 (my references)? if it is not overpassing the X1 I think that it is not worthily the purchase.
Anybody that has compare this phone with players could advice?

 

[Lycosa777]

  I have seen that this phone can be found in the second market for less than $100.
I am thinking to buy and use it just as a player with BT and streaming ability.
Is the M8 hifi performance comparable to the Fiio X1 or X3 (my references)? if it is not overpassing the X1 I think that it is not worthily the purchase.
Anybody that has compare this phone with players could advice?

I would definitely choose the X1 over the M8 for musical enjoyment.
The M8 sounds good, but not what I would call hi-fi. (Boomsound via HO is terrible)

 

[obelisk619]

Does anyone know if there's a difference in sound quality with the regular M8 and the CDMA one(e.g. one from Verizon)

coz on gsmarena, the regular one is the only one that has the 24-bit/192kHz audio. 

Although I have the cdma one, mine can still read a 24-bit/97kHz track (haven't tried any higher kHz) and unfortunately I don't have a regular M8 nor do I know anyone who has one.