I've always disliked BC's energy, I don't like the name, nor the possible ways you can use it.
EU was my first energy unit, then MJ (which I quickly skipped over) and now it's RF.
I had a somewhat similar transition, actually.
First, back in 1.x to around 1.3ish, I used IC2 as my primary power. Oh sure, I used Peat Engines to run all the little Forestry machines, but that really felt more like an ingrained part of the setup, a multiblock that required peat to run so to speak. But for everything else, I generally made do with an electric engine (before circuit boards came out, so it was a flat 2 MJ/t output) until I had some biofuel going. But I really only ever used the biofuel to run some biogas engines to the lasers to get my circuits going for the Logistics Pipes (because using circuits instead of gears was just crack). Primarily, I used a bunch of geothermal generators using Teleport Pipes and a Pump system to pump lava to my setup. Back in these days, Nuclear really wasn't worth the cost investment, unless you went full CASUC.
Then TE came out, and all that changed. IC2 was still useful, Nuclear got an overhaul and was actually worthwhile, although it was still easier to spam geothermals. This is before the EX branch still, mind you. But TE brought with it upgrades to everything I had been using BC for, albeit more expensively. I felt that they were a good fit, price-wise. You start out with pipes, then upgrade to ducts. But more importantly was the Redstone Energy Cells. Finally, you could store MJ as a raw energy source instead of needing reserves of fuel to produce power on demand (which was really harsh on your biogas engines). It also brought some very useful machines, such as Aqueous Accumulators and Igneous Extruders. It also brought ore processing to the table. It wasn't as amazing an ore processing setup as IC2 had, it couldn't be upgraded to go any faster, but it had the neat trick of being able to be reliable, consistent, and easily automated. This was the quarry output of choice for me. I used IC2 when I need to run a batch of something *now*, and I used TE when I was just processing a steady supply of stuff. It also saw a significant upswing in the usage of MJ by itself rather than simply using Electrical Engines. Magmatic Dynamos slowly replaced Geothermal Generators.
Then the EX branch and the Forestry Multiblock Incident came out, and then RF came out. I immediately made the switch to RF, and have never looked back since. I use Mekanism for 'craft on demand', TE for 'slow but consistent production' as well as utility, and everything runs on RF. I use MFR for automating my renewable resources, rather than Forestry. I use TE for getting things around rather than Buildcraft (using ducts instead of pipes). I use Big Reactors instead of IC2 Nuclear. And I'm having a blast doing it!
