Okay, let's start with the downside. This player doesn't do folder navigation. If you have your MP3s properly tagged it'll let you select an artist or album (or a filename, even without tagging) but that's not really a substitute. The battery life is average. What it does do well is a) remembering the current track when you switch it off, and b) genuinely random shuffle play. These are things that the Philips SA2620, a more expensive player with a far better battery life, doesn't. Despite using an internal database to organise music like the Philips, it also switches on and searches for new tracks quicker. Maybe we could mate the engineers involved in producing these things and the end result would be cheap, capable players that don't omit basic features? Folder navigation aside, it'd be useful if the Matsui saved power by switching the screen off after a few seconds, which it doesn't.
Physically the thing is a fairly standard size, in a shell that looks a bit like a futuristic escape pod. The menus are simple. It has the obligatory hold switch and a record function that no-one I know ever uses. Catalogue returns turn up with great frequency on eBay, to the extent I got a used one for £3 and another with accessories and a four-pack of Energizer batteries for £6. This is an entirely reasonably price for a 2Gb player to use as a shuffle player that you can put normal AAAs into when your rechargeables are flat, and a good partner to the SA2620.