I responded to your post on xda but might as well respond here too.
So I am currently working on integrating apps2sd in to my rom (fresh rom) because users who currently have apps2sd on their phones via modaco are receiving errors during install.
I have been working with apps2sd and getting it in my rom for 8 hours now and personally I have come to dislike it. It is a wonderful amazing idea and will be great once it's supported by google or HTC.
But think of it this way... apps2sd stores all apps on your SD card. nandroid doesn't backup your sd card or do anything with it. We have all come to rely on nandroid but if you need to restore because an app you installed broke something and that app is installed on your sd... nandroid isn't going to remove it.
Something to think about before everyone starts using apps2sd...