Hard to go wrong with an AC110
Two things can go wrong with AC. AC is the only brand that you need to remove the motor to clean the impeller, and over time, the O ring will fail and leak just like any canister. When the AC foam get clogged up, pressure will build up and there is a risk that the foam will pop up and drip water from the top.
Penquin is the best bang for the buck, exceeding the performance of the more expensive Emperor. Emperor has the non-essential spray bar and double impeller design that creates more complications to go wrong.