my option was choose super card for 1/5 price 20 euro, and now with superfw ise really promising, maybe games like doom are excesive for the cart but for example mario kart super circuit now runs at full speed for me
the supercard is the only i had for gba and i bought the last year because it was just for test, and was so much useless, but now with superfw i see so usefull
I've been downloading all the games in bulk and automating sorting them into a structure I can navigate on a flashcart, 64 should be sufficient to store basically all games for the GBA, not that all of them will work on a given flashcart due to missing hardware.