Bought one of these to increase my W595 memory from 2GB to 4GB, so that I could use it as my main MP3 Player instead of my Phillips. I wanted to keep exactly the same albums and as my Phillips was 4GB this card did the job.
I connected my phone via the data cable to my PC, then copied my music files and folders directly to the card from Windows Explorer. I did not use the PC Suite software and I am not sure if it would have been quicker to do so using an adapter plugged into a USB slot, I suspect not.
I copied all the albums over, totaling 586 files, or 2.86GB in 26 minutes (just under 3 seconds a track) - slower, by quite a bit than my Phillips MP3 player.
Once the songs were loaded and the Phone disconnected from the PC I decided to give it a try as there have been some Sony Ericsson Phones that seemed to have a lag at which time the phone temporarily freezes between selecting a track and playing it. I found no such problem on my phone at all, it played within a second of selecting a song at random.
There were obviously no compatibility issues at all, and this tiny little card, at least the one I received from 7 Day Shop, came in a nice little case with the adapter so that it can be used in a card reader as an SD card. I mention this as it seems not to be mentioned that it is supplied on Amazon. I was not expecting this so this to me was a bonus.
Excellent value at just £10.