I have been using SE W580i since last 8 months. Till now I have not faced any difficulties with the phone. I purchased it fior 10, 990 and right it is sold at arounf 10, 500. This is the best part - the price drop for this model is just 500 Rs. since I purchased. So, there are chances of getting good resale value.
Coming to the+ points of phone:
=> Good looks
=> New Walkman Interface
=> New Fitness Application
=> Nice Sound
=> Light which changes colour on both the sides of the phone
=> Very tough to change sim. 2 reasons, removing back cover is really tough, and inserting and removing sim is also a pain
=> ok ok camera
In a nutshell, its a good phone which gives you value for money. You are not going to regret your purchase at this price.
People looking for good music phone with elegant looks will surely be happy with this phone.