Something to consider is also the meaning of the songs. While Giorno's theme is certainly more exciting and pumps you up, Brothers goes in deeper on the guilt and determination both Ed and Al have to endure due to their misguided, but well intentioned actions at the start of the series, and that despite what they go through, they'll always have each other. That speaks to me more than Giorno's theme. But again, it's a matter of tastes.
