Couple of friends pulled me into Tekkit. Impressed by the various machines, I began to try to play around, but the recipe lists don't really differentiate between which mod adds which content, and my friends aren't exactly too enthusiastic about figuring it out.
All I know is my first functional creations are "Quarry" machines that I believe are parts of Buildcraft.
Elsewhere I saw a mysteriously closed thread mentioning that Buildcraft is a bit of a resource hog, had some original piping issues, and just not as sophisticated as Redpower. Can Redpower support everything that Buildcraft can do? (literally or spiritually) For example can I still set up automated quarries? It'd be nice to know before I get too used to Buildcraft's features.