I agree, they are very easy to clean and prime. And nothing beats the prices... The only disadvantages that I can see is that they are somewhat difficult to integrate in existing hoods, compared to a canister. Also, I like to cover my tanks more or less completely with glass... the hot design makes that a little difficult.
I was a little surprised to learn that the AC mini, 150, and 200 and 300 all have the same little pump motor, and so different throughput.
After getting used to the "new" noise I am now quite satisfied with it. I like the adjustable flow control... but I don't use it because I add CO2 into the inlet, which builds up to a bubble when employing reduced flow.