I have only used my CFC. It works. It's fast enough.
But I want to trade it for a more efficient, easier to clean Immersion Chiller.
I believe a person can build a 2-pipe IC for very cheap that can perform better than the average CFC and requires very little in cleaning and maintenance. I know Jaded Brewing makes a few models using multiple tubes. This kind of design is, in effect, like having 2-3 chillers running at the same time. The length is shorter, so the water doesn't warm up as much halfway through. It has more cold surface area than a longer single tube chiller.
And clean up is simply rinsing off with hot water (collect a bit that first comes out of the chiller) and let it dry. With a CFC you can't see how nasty it is in there, and it's a PITA to clean inside too. I once used my diptube brush inside my CFC and was amazed at the amount of blackish gunk that came out when I was sure I was rinsing well enough after each brew. Since my brush was not long enough to reach the middle from both ends, I am sure there is still some gunk in there.
Now, with a pump, I can sanitize it during the last few minutes of the boil, just as I would with an IC, but I'd still like to be able to SEE how clean it is, AND get improved performance from a multi-tube IC.
Plate Chillers are great for pro brewers where using an IC would be impractical with their equipment and the batch size. CFCs are efficient too, but in my experience still leave a bit to be desired.