Oh wow, that's interesting. Thanks for sharing. I wonder their differences. The 507 is already minimalistic the way it is, if the 505 would reduce an aspect of it what would it be? This is another reason why I like the Sony, and the way they design. Their pricing, and the value and intrinsic value you get. The build quality on the 507 (I got mine today by the way, now it's charging. Silver) is superb, and from my experience owning the WM1A and AK70 the battery is apparently more durable with the Sony. Both durable in operation, and in the long run/usage. A great player nevermind if you're a collector or someone who is looking to own only one DAP. The Walkman UI has also this timeless design to it as well, which I like. Checks almost all the boxes for me; small, lightweight, good-sounding (though not the best), 4.4 BAL output, good driving power, not bassy, extended treble, excellent details, what else.. streaming, durability, responsive functionality, not childish design, and as an extra, a cool cassette screensaver