Available in 2GB(A805), 4GbA806), and 8GB(A808) capacitites, the specifications of the NW-A800 series are certainly up there with 
the Sansa and utterly trounce the nano. Its 2in (42 x 31mm) 320 x 240 pixel screen is the biggest of any player in this class and is nearly twice that of the nano, battery life is as high as 30 hours while continuously playing music, and the pièce de ré·sis·tance is MPEG4/H.264 video playback at up to 30fps - twice the rate of the Sansa - which it can keep playing for up to 8 hours. All this and it’s still only 9 x 44 x 87mm which is positively anorexic compared to the Sansa. All of which puts the Walkman way out in front of the competition, but as we all know there’s more to these things than just statistics so let’s see how it performs in use.
The moment I set eyes on the NW-A805 I was won over by its sleek lines and well proportioned layout. The large screen, the subtle curve of the sides, and the little bits of chrome trimming combine to make this the best looking player on the market. As a conceptual design the iPod would probably win the award but on looks alone the Walkman wins hands down.
It’s ironic, then, that I don’t actually like the feel of the Walkman in my hand. Super slim design may be great for your pocket/purse but, when handling a device, my big hands like to have something to get hold of. When using the A805, I found myself feeling paranoid of dropping it all the time and it was a real pig to pick up off the table. Of course I have the same problem with the nano, so it may just be me. Personally, I find that the Sansa is the perfect thickness and shape to handle comfortably.
TrustedReviews - Sony Walkman NW-A805