I have only bought quilting fabric from:
MSQC
Connecting Threads
Craftsy
I have bought fashion fabric from Fabric.com too.
I am in Canada and have to consider exchange rates, shipping (cost and method) and duty. I stopped buying from fabric.com when they would not send my package via USPS and would send it via UPS. UPS charges Canadian outrageous brokerage fees and I will not shop with any company that only uses them.
Craftsy shows me the price in Canadian dollars and CT does the brokerage, so I do not have to worry about duty.
It has been a while since I ordered from MSQC, but I was happy with the products, service and shipping when I did buy.