A hybrid build is anything with between 25% and 75% troop and spy buildings, it has nothing to do with stats.
You could basically imagine a build with 24 guilds on lowlands, 25 colonies on highlands and 25 T6 (elven whatever housing). This would be a hybrid build (it follows hybrid mechanics, see Bellemorte's thread), as it has 30% spy buildings and 70% troop ones (approx...). The stats would however make it look like a hitter.
Balanced buildings have a higher troop count and higher total stats, will give you a slightly higher plunder compared to attack buildings. Building one balanced building will also allow you 26 attacks per unload instead of 24 (5 minutes longer regen though). Up to you if you prefer looking a bit more offensive or not (PS: the end bonus should be slightly higher with attack heavier builds as you'll do more damage).