I've used EZ Flow and Backscratchers, I like Backscratchers system the best. I don't do many wraps anymore, but I found Backscratchers has more options for materials then the rest. I really like thier brush on resin, it helps for control when you are starting out. I'd use the brush on for the first layer to get a good controlled start, then I'd switch to the bottle/tip, so I could use the pressure of the tip to "soak" the wrap. Does that sentence make sense? Anyway, it's really up to you which system you like, but for ease of use, I think it's Backscratchers!
Shiloh