The plastic casing is a step backwards from the S639F, which was built from aluminium. The use of a cheaper material hasn't resulted in a cheaper price, though. Worse than that, though, the bundled earphones aren't anything like as good as those bundled with the S639F. Those were just about good enough that you didn't need to upgrade to a better set, but the 'phones supplied with this S Series player are decidedly underwhelming.
Positioning the toggle switch for the output mode on the same edge as the hold switch might cause annoyance if you're memory is as poor as mine but otherwise the control layout is good.
On the plus side, the screen is now larger (at 2.4in versus 2in previously) and although it retains the same 240 x 320 pixel resolution and is consequently less sharp I think Sony has made the right call. Let's face it, having to squint to watch videos is hardly ideal, so a bigger display is worth having.
A stand that sets the S544 at a 45-degree angle might just be the easiest-to-lose accessory I've ever seen included with a portable media player, but it is useful if you want to watch videos and have a solid surface handy to place the player on.
There are less software features with this generation. SenseMe channels are no longer available and nor is Intelligent Shuffle. While it's entirely possible Sony concluded these features weren't actually used by the majority of Walkman users, I can't see what benefit removing them has brought. At least the otherwise unchanged interface is still as good as it has ever been.
There are a few niggles, though. Podcasts are lumped in with all the other audio files, which can be annoying if you want to put your entire music collection on shuffle. There's no on-player facility for creating playlists either, which is something of a glaring omission.
The S544's FM radio is entirely similar to that of the E443's, with pausing and recording both possible. Again, it's not a feature I'd ever use myself, but it is well implemented. Audio recording (in 96kbps, 128kbps or 160kbps MP3) is also present here.