We have a Xylem Tech cart filler and its definitely the way to go. You still need an operator but that one person will be overseeing the machine ensuring its fed with enough carts and mouth pieces. They are also QCing the carts as they come out which is a big plus. We usually do 3000 cart batches at a time and have anywhere from 1-40 carts not pass QC which is extremely good for failure rates vs the alternatives. our fill lines are also visibly higher than ever other cart in our market as it caps the cart less than half a second after filling it.
This is a video from our initial start up.