Well, that's your opinion. As a modder, I find Buildcraft superior, because it's open source. That means that I can interface with it and change it however I like. I can't do that with Red Power without getting my head bitten off. If I don't like a mechanic in Buildcraft, I can change it or add my own pipe to it.
If I had to choose between Buildcraft and Red Power, I'd choose Buildcraft in a heartbeat, because without it, there wouldn't be any of these cool mods we like today. Thermal Expansion started out as a Buildcraft addon, Forestry started out as a Buildcraft addon, Railcraft started as a Buildcraft addon, heck, even Red Power started out as a Buildcraft addon before moving on to become it's own mod.