I have been using Eagle since Fall 2010, and have done some pretty complex designs with it.
You can fit an amazing amount of stuff on 1 schematic sheet, I have not found that to be an issue.
I have done All my designs as 2 layer PCBs. With 4 layers, the price for a board jumps up. I have not even looked at 16 layer pricing, that's really for commercial designs.
I try to limit board sizes to 100mmx100mm, as prices for boards also increase a lot above that size.