with a rasberrypi you have to run a pruned node, or connect an hard disk via usb2(there is no usb3)
with a bananapi you have a sata port so you can connect the hard disk directly. So with a bananapi you can run a full not pruned node. Everything else is almost equal.
I don't like pruned node because, if for some reason I have to perform a rescan I have to download the entire blockchain another time.
Also Im not sure if pruned node relays blocks.
Why would you need to run a pruned node with raspberry pi? just run a regular node. Also, pruned nodes only relay latest blocks received, but not the whole blockchain.
because the sd card is too little, I don't know if an sdcard is able to store 150gb of data. usb is very unreliable and you end up with a corrupted blockchain.