I have used them both. The Ampmaster 3000 that I used on the last tank never leaked, although I did have to replace the seal once because the motor would not start back up after I shut it down to clean my skimmer. It was too much friction of the shaft.
The Seqeunce pumps I have are great, although both of the newer "Reeflo" models did have small leaks/drips that eventaully stopped. For some odd reason the bolts connecting the pump head together were barely tight - as if somebody forgot to finish bolting the thing together. This was on both pumps mind you. And more recently, I noticed that the bolts connecting the pump head to the motor were loose, although this did not lead to any leaks. So a word to the wise, keep an eye on the bolts.
