Share your experience!
I bought my MW1 just the other day and been trying different ways to come up with a solution...
Problem; while streaming music from the phone (normal player or Spotify) the music gets chopped up in tiny tiny pieces (stutter) - last for a few seconds up till 20sek(?)... from time to time this repeats it self every 30 sek to 1 minute ((in which cases I freak out and turn it off or start listening to music I put on the memorycard)), but in periods it works ok for a longer time.
Other times the music just stop! ....and then continue again after a short period, and it has also disconnected with no reason.
I tried turn off/on + rebooting my phone, factory reset and so on....
It's reeeealy frustrating... been using MW600 before without issues.
Model: Smart Bluetooth Haedset MW1
Firmware: 0.1.E.1.4
Paired with: Samsung Galaxy Note II
We have escalated this problem internally. Also see this thread: http://talk.sonymobile.com/thread/112907.
Thank you for that information, Rickard. Good to know Sony is aware of the topic !
Dear Sony.
I just updated to the new firmware - 0.1.E.1.5 - and the problem presist!!
Problem; while streaming music from the phone
1st problem - the music stutter - last for a few seconds mostly.
2nd issue - the music just stop! ....and then continue again after a short period.
More of the 2nd issue now after update - the music just stops for a few seconds now and then...
Very VERY annoying!! - but I'm sure Sony working on it... any update on this topic Rickard?
I have only received my headset this week and initially it didn't appear to have the problem however it has now started to do the same but only with Spotify. I haven't used any other music streaming app - if you guys can suggest others for me to try out then I will give them a whirl too!
Weirdly it seemed to be worse on certain of spotify's channels than others but don't know whether that was because I was swapping between them when it started happening. Is it a buffering issue - not entirely sure of the technology. I have the latest software versions for both the phone app v1.1.26 and on my device 0.1.E.1.5. I have had the issue with both wifi and 3g - I did speed tests using both and I have great download speeds where I am so don't think this is the problem. I also tried swapping out the headphones in the bluetooth device but that did nothing to the stutter but did give me a much louder music experience.
I have listened to an audio book on Audible and didn't get the issue and I have listened to some music on the Walkman app and that had the odd tiny stutter. The other time I got a stutter is when I had moved a sufficient distance away from my phone that it was having a connection problem rather than the streaming stutter. I would also say that I have used the device as a radio and that seemed to work perfectly on a car journey.
I have tried the device mainly with my Xperia P but have also connected it to my son's Iphone 4s and my husbands Samsung Galaxy 3. Over the weekend when I can surgically remove them from their devices I will try streaming on their phones too just to confirm that the issue is not device based which judging from the feedback on the Play Store comments I don't think it is.
So that's my two cents worth. Obviously the powers that be at Sony are aware of the issue and hopefully will come up with a solution.
Bought this headset yesterday hoping that all early problems had been solved!
But I turned on the headset and got info about new firmware ( 0.1.E.1.5) available and did an update.
Holy shit! No playback works at all, everything stutters every 10 -30 sec. Either the music skips or goes quiet for a few seconds. This is during movie playback or music playback from my Galaxy S3.
Its impossible to listen to music with this headset and I cant believe Sony released this firmware that dont work at all.
I managed to do a sonyupdateservice and reset the headset to the earlier firmware (0.1.D.0.6).
Now the music and sound dont skip at all! However its anoying that the phone reminds me of a new firmware everytime I connect to headset.
Sony!: please fix this headset firmware ASAP! Its ridiculus that we have paid this much money for a product that dont even work with basic tasks as playback.
Had the same problem: severe stuttering/cut-outs. Factory reset didn't help. Had the problem since firmware version 0.1.E.1.4.
Got the advice from Sony Support to use the Update Service, and that worked beautifully. The Update Service did a downgrade so the headset now has version 0.1.D.0.6 and the stuttering stopped. 
/M
The problem will be fixed in the next update for MW1 but i don't have any date for release.
Until the next update is available i can only recommend that you downgrade the headset using Update Service.
Anyone with my problem? I havent acces to Sms and call log apps, though I can acces to my call log via the round button, and I cant manage to make text to speech to work. 
These issues appart, my device works perfectly.
Check this thread : http://talk.sonymobile.com/thread/127086?tstart=0