Bought for 50 GBP from an official Sony Store in my area.

Service at the store was excellent; direct, approachable and fast.

USES:
I have used this for jogging and at the gym

BUILD QUALITY:
Rugged, fairly water-resistant, although it has 'blacked-out' on me a couple of times after my more sweaty runs; only after laying it by the window to dry did it start working again.

No problems with battery life - easily 4-5 hours on a full charge - you can also charge to 90min capacity in a matter of 5 minutes.

SOUND QUALITY:
Average; much like a normal 10GBP pair of earphones. The sound variability isn't great; i'm usually up to the max volume if i'm running my the roadside and listening to mellow jazz or piano. Difference between volume settings is not wide either.

EASE OF USE / FUNCTIONS:
Zappin - a new feature which lets you preview tracks; not too useful - i would presume this function was for those who are looking for a particular song ; but having to scroll through the large number of songs, listening clip by clip, is no replacement for a screen which lets you READ through t he song list.

Buttons are intuitive, standard issue.

Compatibility with your computer is also fairly simple - drag n drop works, as does the Sony Walkman software which is a variant of it; but slightly easier to use as you do not need to select any folder whatsoever.