personally i think the best sort of firmware to be on would be 6.x for old3ds/2ds users.....would be good if we could get a 2DS downgrade method, so then everything except the n3DS has a offline solution(actually even the n3ds is offline, but limited to cubic ninja atm).....plus then they have working 6.x save encryption
Has the most entry points... has 0x2F keyslot init'd... I don't think it's a subjective thing.