I LOVE designing my quilts -- I use both graph paper and EQ (now 7). EQ frustrates me -- here is an example. I designed a quilt with 56 blocks, there are 4 block sets that are the same pattern and different color ways. With EQ I was not able to find out how many of each color way I needed. It does not tell me how many pieces I need to cut of each block to do the whole thing. I wound up counting the blocks by hand using the printout of the quilt and doing my figuring by hand.
What I find most useful with EQ is the fantastic assortment of blocks -- I have made a lot of wonderful quilts using the blocks in EQ and BlockBase. EQ also updates their fabric selection regularly -- I find I don't need to scan in my own fabrics since I can get most of what I want in their fabric assortment.
I have been tempted to buy Quilt Pro because I have heard it is really flexible, but it takes a lot of $$ to buy a new program -- once you have bought one they offer good deals to upgrade to keep you hooked.
This is why I still use graph paper.