I started off with Ai, so that's what I had learned. I was compelled to learn CorelDraw when I upgraded to some software that had Draw built into the interface. I have actually come to like CorelDraw compared to Ai.
The only advantage that Ai has to me now is if I'm know I'm going to be using other programs within the Master Suite. Even then, I can always export my CDR file as an Ai and then continue on with my work in those files.
Also printing for sublimation actually works better as far as getting the colors right with Draw then Ai.
Also one clear advantage that Draw has right now with x6, that you don't have with Ai and Ai really needs it, is multi-core support.
Given that I'm one of those d**ned cheap shirt guys, it looks like CorelDraw has some advantages for me compared to Ai now. I had to use a lot more plugins to make Ai fit the bill compared to Draw.
I will still use Ai on occasion, but like I said, Corel seems to be becoming more and more my preferred program when doing my embroidery and sublimation designs.