Mine is pretty big, I'd say about 30 inches or so. I've had it about 20 months, and it came in around 8-10 inches, so I guess the growth rate has been about an inch a month. I have mine with a smaller motoro ray and an Asian arowana. I would like to sell the ray as it tends to eat way faster than the AUL. Given how big a motoro ray can get if it eats as much as it wants, well, I better get rid of that ray.
I am hoping my aro (a BBXB of about 10 inch size now) will leave the AUL alone if the AUL is always way bigger than it. That is my hope anyway. I highly recommend an AUL to anyone with a tank of 300 gallons or more. I have no plans to import more, but anyone can do it; it is not hard to do.