After using the Aqueon 30 for a bit now, I can say it's definitely not being replaced with another Aqueon if it breaks.
One thing, when doing PWCs, you can't let it run. The intake tube is so sloppy and loose on this model that the instant the water goes below the in-tank pump itself it starts to suck air and lose it's flow. Every other HOB I have you can drain a tank down to the strainer without ever losing flow, worrying about backflow or having to restart the pump.
Here's my take on the Aqueons (and I'll address what you say below as well): I have been using them for a few years now, ever since we put a QuietFlow 55 (now discontinued and replaced by the 55/75 model) on our 60 gallon goldfish setup (now cracked and destroyed) some two and a half years ago. We also have a QuietFlow 20 on a 10 gallon, and I do know what you mean about their intake stems seeming weak and cheap. On the 55 model in particular, the intake pipe moves and leans out of place in the attachment hole like mad, as if it's going to totally fall out.
Now, with regard to the pump stopping during a water change -- I have not experienced that yet with my Aqueons. In fact, when I had both the 55 and an AquaClear 110 running on the 60 gallon together, the AquaClear would quit pumping and sucking water way before the water line got anywhere near its intake strainer...the Aqueon continued to pump water back into the tank with an aggressive water return.
Second, I left the stock filter in it, and wow, what a piece of garbage. It made the water stink. STINK. Something in the floss or the carbon. PEEEEUUUUUU. And cloudy too. The water wasn't milky, but it wasn't crystal clear like I want in my tanks. There were no fish in the tank at this time. I took it out and 80% of the carbon is bunched at the bottom of the filter. That's no good. It needs to stay spread out to work right.
Not sure what you mean by "stock filter," but if you're referring to those carbon cartridges that are designed for the Aqueons, have you ever tried rinsing them out in used tank water? It's actually funny that you mentioned this, because just yesterday, my wife was saying that the water when you walk past our 10 gallon to go either up or down the stairs STUNK to the high heavens...I have noticed that our tank does have a strong chemical-yet-earthy smell to it when you go right up to the water, and I understand that you WANT an "earthy" smell to the water...it means it's somewhat healthy and clean. The "chemical" part I chalked up to all the Prime we use in this tank because I am doing DAILY water changes on it due to the horrendous goldfish overstocking.
Still, the smell bothered her, so today I changed out the QuietFlow 20's cartridge for a new one, even though the same cartridge has been running on the tank since we set it up and I have only been doing rinse offs in used tank water...no replacements until today. I fear we will experience a mini cycle now because of the bacteria being lost, but I am also hoping the beneficial bacteria that is supposed to grow on the Aqueons' blue plastic bio grid pieces throughout the filters will make up for this.
The loading of debris on the cartridge of the 10 gallon -- even with four over-eating goldies -- wasn't that blackened or browned all that much, believe it or not...sure, it was packed with sucked-up debris and solid particles in the floss pad, but it wasn't as bad as you'd think given the circumstances of four goldfish in a 10 gallon eating twice or so a day. Still, I changed out the cartridge due to the wife's analysis of the horrendous stink...
I swapped in the BIO3 generic replacement and within hours it didn't stink as much and the water became crystal clear, as evidenced by my tank pics on here. No it's totally odor free, aside from normal mild aquarium scent. The BIO3 also allows you to toss the carbon packet and keep the blue foam filter intact when cleaning.
The filter will stay on the tank as it seems to be doing it's job, but I won't be using another one, and I'll never buy those Aqueon cartridges again. I'm glad I found out that my other cartridges fit.
All the above of course is just my personal experience with this model. I'm sure others differs.
Indeed; I would buy another Aqueon filter in the future. I like them. It's just the routine of the cartridges that takes some getting used to (whether they need to be thrown away after awhile or simply re-used with dunks in used tank water, etc.)...as for the cloudyness, well, this QuietFlow 20 seems to be doing a great job keeping the 10 gallon goldfish setup crystal clear...of course, I'm doing daily and sometimes bi-daily water changes on it, but still, the filter is doing something to aid in keeping that water pretty pristine looking...