What kind of problems do you mean I want to be aware, as far as I know coco is fungisidal (so no kind of bad stuff can live in it), I reuse coco. At the moment I grow 10 starins in 1.6 liter containers and ofcourse feeding is the almost same for everyone. I use coco bricks flushed in the pillow case. One brick gives 4 liters and costs 1 USD, also you need 3 times less volume of coco than soil, so your excuse about expensivness is not accepted
The only major disadvantage in coco is elongated veg stage due to the root mass growing, but payed off by harvest. I suggest you to maintain a couple of girls in coco along with your soil grow and make an experiment.