I have been using the SE K750i for the past few months and its sound quality thro' headphones is simply superb! Speakar output sucks but that is not surprising. Thro' headphones the MEGABASS equalizer setting provides the best result. Sometimes I forget that I am listening to music on a phone and not a standalone MP3 player. FM radio sounds good too.
Last week I had the opportunity of using the N73 for a day. Its a good phone. Big display, great sound thro' stereo speakers etc. But when using the bundled earphones, even with the equalizer on BASS Booster, bass doesnt sound that great. Mid and high frequencies sound ok but the bass is a real downer. I was quite surprised by this. I was hoping to migrate to this phone after a few months, but now I dont think I will. Sound quality is very important to me as I listen to music a lot.
Nokia is going to introduce a music edition N73 but if the basic hardware is going to remain the same then I dont think even sound on that phone would differ much.
MEGABASS from Sony is their trumpcard. All phones that have MEGABASS sound good even with bundled earphones. Nokia has to come up with something that matches MEGABASS. I dont think just rebranding phones as music editions is going to work.
Even Sony, in its infinite wisdom hasnt given the MEGABASS option in K790i because it is branded Cybershot! Why would they want to cripple something that works well is beyond me!