You are correct in saying that they are different, but as it currently stands there is almost no difference. I have not seen a single engine that creates RF that isn't a simple plug-and-play style setup, regardless of what mod it's from.
And Buildcraft isn't like that. The additional requirement of having to go into wooden pipes hardly counts for much. The various tiers of pipes? TE has 2 tiers that's all you really need. I certainly don't want to have to keep rebuilding my power network.
If you are talking about foristery boilers then allow me to remind you about big reactors. They can be as simple as the boilers or as complex as IC2 reactors if not more so.