I haven't owned an S30, but I have owned the 800, a slightly earlier model. The 800 was an ok device, but it had 2.5 flaws that really hurt. First, there was the infamous recharge issue with the NiMH battery that came with the 800; the 800 had this amazing ability to kill batteries when recharging them. Luckily for you, the S30 uses alkalines, so you'll be fine. Second, and this is a more trivial complaint, but the soldering work seems poor on the 800, as my back button no longer works for no good reason, and I've heard sporadic reports from other owners. Lastly, the software it comes with(the same that the S30 comes with) sucks; RealOne Player is pretty sad as a music manager, and was more effort than it was worth. I ended up using an add-on for DB PowerAMP to do my loading, as adapting to RealOne really wasn't going to happen.
Other than that, the player was good. It went forever on a charge, was easy to navigate(especially with the backlight), and as far as I'm concerned, sounded good. As long as you can find different software to upload music to the player, and Sonicblue has taken care of the button issue, I can't see why the S30 wouldn't be a good player to have.