If you want double din with GPS, DVD, ipod e.t.c... Don't mess around with the lesser products. Stick with Alpine or Pioneer. Those cheap ebay HU's are exactly that... Cheap. Their software and hardware is questionable.
I've used both systems and am currently running with a Pioneer double din touchscreen in the subaru (gps, dvd, mp3, wma, blueteeth, ipod, SD... blah, blah) and it's brilliant. You can't beat pioneer for their user interface.
Alpine are also great... I've resorted to an Alpine single din HU in the disco with a lowly ipod interface.
I would like to install a double din unit in the diosco at some stage (if I keep it), so will be watching this thread with interest.

