I have the Deltec 500M on my system, works like a champ with no problems, just keep it cleaned out on a regular basis like any other one. Motor went out over a year ago and had to take it to Richmond to get it fixed, could of mailed it but wanted to get it back working, motor was $90 and only available from Deltec. Made me wish that I had bought a GSA for less money, bet a replacement motor is alot cheaper also. From what I see the stirrer bar is different between the Deltec and the GSA, probably doesn't matter, the GSA may actually do a better job than the round metal stirrer on the Deltec.