I have read that, which is why I was confused;
As it says; "Guaranteed that data arrives" I can say seems to hold true as long as it is received as fast as it is sent.
Also it appears to arrive in order and error free from what I can tell so far.
The literature in QB64 help in the program says data may arrive at different times, so that's still slightly confusing.
But, it does seem to work, like I said as long as data isn't sent faster than received.