For me, Computercraft has a similar function to MFR. One of the reasons powercrystals says of his mod is that it automates alot of things that are tedious to do otherwise. With computer craft and basic Lua knowledge it is easy to integrate turtles and computers to handle tedious tasks for you. So the shearing turtle is no less cool/imaginative as the MFR rancher and both can be used to make interesting builds.
I don't agree that they are particularly overpowered either. Yes turtles are cheap to build but the most complicated things I have seen people do are automated mining machines, automated tree farms, automated building, cool sorting systems and fancy control systems. The automated mining machines take a long time to program if like me you are learning LUA but even of you already have experience it still requires a lot of thought. You still have to use Diamonds and they are roughly comparable in cost to a modest frame machine. I think frame machines are easier to set up as well (if you are making your own code). They are cheap compared to (not Gregtech) buildcraft quarries and very cheap compared to (gregtech recipes) quarries and Steve's carts galgadorian drill but they are still a cool way of gathering resources, are difficult to code well, and require diamonds and fuel.
MFR has cheaper tree farms. They are good at building simple structures in a faster and more accurate way than players and fillers aren't exactly galgadorian are they? I have seen a computer controlled sorting system on these forums that looks like it has similar functionality to applied energistics. But if you have gone to the effort of making that then I think you deserve to not have had to make a ton of diamond assemblies. Also, some of the peripherals added by miscperipherals to assist in creating computer sorting systems are pretty expensive.
It is still possible to appreciate logic whether its in the form of a physical gate or a line of text that says something like if x and y == true then z = true.
Sorry for rambling, and if I have missed the point of anyone's arguments its not because I am being deliberately ignorant. I just think that turtles and computers are an excellent tool for any minecrafter wanting to get automated. And an awesome sandbox machine in a sandbox game like minecraft. I think that is fitting.
Finally, I would suggest that some of the best new mods of recent times like Thermal Expansion, Minefactory Reloaded and Tinker's Constructs are as good and popular as they are because they liven up the early game.