A little hint with regards to AC 110's, I never unplug mine during water changes. With extension tubes attached I can easily get a 70-80% water change performed, with the filters still running during the entire process. I only shut them off during actual filter maintenance, and I don't attempt to restart them unless the water level in the tank is near full. This way they always prime, every time.
It was always loud, eventually some sand got in it and I needed to replace the motor and I just had enough frustration with the thing and I tossed it.
No need to replace the motor, the motor is a sealed unit. You just needed a new impeller shaft. It's a $5.00 part that can often be purchased locally if you ask at your LFS.
http://www.petdiscounters.com/Hagen-AquaClear-Impeller-Shaft--110-500-A16551_p_19083.html
As previously stated I have had to change a few impleller shafts over the years due to sand, but even with prefilters these filters aren't designed for large sand spitting fish. My bad, no fault of the filter. I haven't even had to break down and change an 0 ring over the years, not one. But again, a cheap part to replace even if one did this as routine maintenance every 5 years or so. The plastic can't be that flimsy, not if they are lasting myself & others 15-20 years. That plastic is much more durable than it seems on the surface. I just bought another 110 during the Xmas/boxing week sale at Petsmart, even in Canada the total was under $50. Hopefuly I get another 15-20 years out of this one, if/when I need it to replace one of my current AC's.
If companies still made quality products like this domestically, that lasted more than 6-24 months I'd buy them. And I'd pay top dollar for them too.
But there's the problem, everything is now outsourced due to consumer demand. Someone previously mentioned the vaue of work boots, cheapos vs brand name. I guaranasstee you that if you buy a pair of Made in The USA Redwing Boots, and live in those boots during most days, boots that they can be resoled by the manufacturer until the leather is almost rottinging apart, you will never consider the true value of a quality pair of boots, vs cheapos, again.
But for the most part that's not todays consumer mentality, where consumers would rather buy cheap, and replace on a regular basis. Unfortunately you can't always have your cake, and eat it too. This coming from someone who remembers when a regular pair of Levi jeans were still Made in the USA, from Made in the USA fabric, and took a good 2-3 dozen washings before they were even lightly broken in.