[Fungus]

Spring-loaded connectors: no flaws, study and durably, no moving parts and can be swapped out without the chance of ripping or expanding the sockets. There can be bit of play if one wiggles the connector side to side but recessed sockets eliminates this problem. 
 
MMCX: swivel connector eventually wears out connector, dity gets in and cuts out audio, eventually gets loose 
 
standard 2pin: will get loose after swapping out cables. Can happen sooner than later if one tries to jam in a 3rd party cable which has slightly lager sockets than stock cable.  
 
Why? Somebody please enlighten me 

 

 

[H20Fidelity]

I don't know why, but I agree the industry standard needs improving. With an increase of detachable cable IEM at cheaper (and more expensive) retail prices the locking mechanism should advance forward. One of the better cable locking systems can be found on Sony's earlier EX600 and EX1000. Now even they use MMCX. There's simply isn't much confidence in a purchase with detachable cables for me currently. While they'll last a 'a while' I want to see a step forward.

 

[TCD1975]

I don't know why, but I agree the industry standard needs improving.

Agreed ... MMCX are a step backwards. I've come to the point, having had the MMCX connector break on my UM Pro 50 3 times, in 3 different way, that  I'd rather have fixed cable than MMCX again.
 
http://www.head-fi.org/t/709819/westone-um-pro50-vs-w40/60#post_12095194