I have ordered 15-20 times from them. I would say 4 orders included items on back-order. They do ship the other items on time (separately).
However, the back-order items have never come before the estimated date always After. Also, if I pay for faster shipping, they do not honor it on the back-order items when they finally do come in.
I like the selection at TW, but my honest opinion is that "whoever is responsible for the estimated dated" (TW or Manufacturer), it is an "optimistic
date" and, in the meantime, they have your money tied-up.