Rockbox on Sansa Disk Clip Zip

After my beloved Ipod classic got stolen , I needed another mp3 player with the following features
efficient but relatively cheap.

• micro sd card slot to upgrade and swap songs.
• open source friendly.
• can handle various media files other than well-known mp3 format.
• light-weight and portable.
• doesn't attract much attention such as fancy apple products :/
• plays well with DRM audiobooks (audible specifically ).

 I purchased the Sandisk clip zip 4 Gb..and I like it so far,but i needed more.So , dual booting with Rockbox was my choice, the installation didn't take much time , failed first at linux pc but it went OK on Windows 7 , i guess it has something to do with the drivers or the usb-mode.
Rockbox is full of features and highly customizable (I need to go thru the 128-page manual to get a full picture of i'm missing so far). what i liked most :

• plugins such as calculator, alarm , 
• ability to forward 1-2-5 minutes (not possible on SanDisk OS ).
• support of all sort of playlists .
• support of many media format.
• bookmarks and resume from where left .
• customizable .cfg files for settings editing on pc (can be transferred via usb to the sansa)