Plate chillers and ICs both depend on the size and the volume. I have a 3/8" 50' IC that will chill 6 gallons from boiling to 75 in 5-6 minutes flat.
One of my friends bought a plate chiller from that same vendor, and I have to say, it will do an awesome job. With our larger system (55 gallons), the plate chiller does the job by itself in one pass. We can go directly from BK to fermenter. The last time we had to use ICs, we used my IC and another one designed by Jamil Z, and once we figured out to run the output back into the pre-chiller, it also worked fantastic. We were tearing through bags of ice until I measured the output at 52. If you ever get a big system, you will want to engineer your cooling carefully. 50 gallons of boiling wort has a lot of thermal mass.