Interesting.. Okay, here's the juicy bits:
My very first player was retuend to Support a year ago, because it would lock up on switching to 'Aux'. It was also very bad during disk reads (explained below). That player was devided to be replaced (I wonder where it is now..) The replaced player had the Aux issue fixed. However, it still has the disk-read problem.

Now, I got a new, backup player. I've been fiddling with the backup player, and it, unlike the first two, do NOT have the disk-read issue.

The 'disk-read' issue is as follows:
When the disk icon is like: the player is incredibly slow to respond to button presses, etc.
For example, the disk icon is like that, and you send it the 'skip ahead' command via http (using EmpegTray or the Web Interface), and the player does nothing. Once out of that HD mode, the player thinks you've been HOLDING THE BUTTON DOWN, so it starts fast-forwarding. Sometimes thru the entire song, sometimes just for a bit. In either case, you can 'abort' it by giving it another button-press, assuming that the HD icon didn't go back to the bright-middle setting.
Also, during this time, it does NOT want to listen to the remote-control. Sometimes the same thing happens, thinking you held the button down, other times it just dosn't see the button pres at all.

Ive tested both my players wuth the same software/remote, and got the results. The only difference between the two is that my 'backup' was made considerable before my 'in use' one (both still MK2a models, tho.), and the backup has a second HD added. (Although it was the same before the second drive - perfect.)

I'm not really complaining, they're both useable, I was just curious in the difference in design somewhere that anyone knows of?

Me.