I absolutely love them. I'm running a #3 and #4 in my 40 gal. breeder with some minor sand shifting when they are both running. Will probably go to 2-#3's.
Also have a #1 on 25 gal. tall. #4 made a little noise for about 2 weeks then went silent. Guess it needed breaking in. The new ones come with a protective shield for the fan blade and flow directionals attachment. It allows you to let the flow go in all directions or one strong current