I still use it because I find it easier to get IC2 going at the beginning. I am ready to make copper cables before I am ready to make redstone conduits. I build a macerator as soon as possible to get the doubling going. But before long it gets retired and replaced by a bunch of pulverizers. The only IC2 machines I have on my current build are the induction furnace (for the crazy speed), and the compressor and extractor (because there are no alternatives to them). I still use IC2 tools though I guess thaumcraft pick with repair 2 would be better... of course it is much easier to get an advanced drill than that pick... considering all the research you have to do and then once you can make it you still have to get the right enchants on it. I also use the GraviSuitPlate. Not sure if anything stacks up to that.
Edit: One big issue I have with redstone conduits and energy cells (as awesome as they are) is how much space they take up... I chain together a lot of energy cells because I want a lot of storage... and having to put 2 blocks of conduit between each energy cell is a major drag. I have 20 energy cells in my current build and that means over 60 blocks of conduits and cells to find a place for. With IC2 I can stack MFSUs on top of each other. If the energy cells worked like that it would be awesome... or even if you could connect them with one piece of conduit rather than 2. They also comparitively hold much more... it takes a lot more time to empty a MFSU than it does to empty a cube. I wouldn't need 20 if they took as long to drain as a MFSU does. Maybe there should be an upgraded version.
Edit: One big issue I have with redstone conduits and energy cells (as awesome as they are) is how much space they take up... I chain together a lot of energy cells because I want a lot of storage... and having to put 2 blocks of conduit between each energy cell is a major drag. I have 20 energy cells in my current build and that means over 60 blocks of conduits and cells to find a place for. With IC2 I can stack MFSUs on top of each other. If the energy cells worked like that it would be awesome... or even if you could connect them with one piece of conduit rather than 2. They also comparitively hold much more... it takes a lot more time to empty a MFSU than it does to empty a cube. I wouldn't need 20 if they took as long to drain as a MFSU does. Maybe there should be an upgraded version.