I choose E Heroes because they have stronger monsters and their Fusion Monsters actually stay on the field. The Neo-Spacian Fusions can stay on the field, but only if you have Neo Space on the field, and there's no guarantee that you'll be able to keep it there. With the Elemental Hero Fusions, you have good effects and high attack power all the time until your opponent finds a way over them. Also, though both decks have decent effects, the Elemental Heroes beat Neo-Spacians by attack power. All the E Heroes have a decent ATK, while the Neo-Spacians have low attack power, not usually going over 600 ATK. And last but not least, Elemental Heroes have support that the Neo-Spacians never received. The Elemental Heroes received Mask Change spells and more Fusion Monsters which can be easily used to over come almost all opponents. The Neo-Spacians are left with what they came out with, which isn't good enough to stand up to any decks.