What's the difference between this one and a2sd?
I can figure out that it's better because it is like a unique memory while a2sd are 2 different storage and you will stop to install apps when one of them will run out first. Is it right?
Inviato dal mio HTC HD2
Data2sd(ext) is when you move and link your cache and app settings to your ext partition of the sdcard, which may give a performance boost an faster access times depending on your sdcard, but could result in more battery usage.
App2sd may mean two things, one is using the android feature of moving a limited amount of apps to a folder on a sdcard (thus freeing up the internal storage) via the app info screen in android, the other (a2sd/a2sdext) means linking your internal storage to your ext partition and moving your internal stored apps to that partition. This means that you can only install apps on the ext partition of your sd card and that apps cant access your real internal storage anymore unless you reverse the process. App performance may degrade when direct run from a slow sd card.
A solution to not being able to use the internal storage may be a large system partition (445mb+) so that you can push your necessary apps to the system partition and thus utilising more internal storage.
Link2sd allow you to select which apps are moved and linked to the SD card, allowing to use your ext partition and internal storage at the same time, but this makes backup and restore of your apps difficult and may cause problems if used along with android apps2sd.