I've used Emperor 400 and AC110 in the past. If you're looking for a HOB Filter, I think either one is good. AC110 are simple and the flow rate is great. The media last longer. The current from an AC110 can be a bit strong (depending on fish you keep) and no matter on the adjustment, it can still be strong without DIYing it. Emperors seem to aerate the water more. The spray bar can be adjusted to control the flow. The only thing with Emperors are the cartridges that needs replacing. Seems that they need to be replaced more often then AC110 Media.
If you want go Canister, there are plenty of Canisters out there that does a good job. You can go with brands like Eheim, Fluval, or Rena, but JBJ makes a good Canister filter that comes with a UV sterilizer that I've used on a 50g tank before and it worked real well.
If you want go Canister, there are plenty of Canisters out there that does a good job. You can go with brands like Eheim, Fluval, or Rena, but JBJ makes a good Canister filter that comes with a UV sterilizer that I've used on a 50g tank before and it worked real well.