Hi and welcome to R2R!
I have a 75g Aqueon mixed reef that I set up last September as an upgrade from my 56g Aqueon column tank.
I am very pleased with the tank itself. I have had several Aqueon aquariums and never had a problem and I have had some of my aquariums up for 10 yrs.
The dimensions of a 75g are nice in that you can have some of the bigger fish like a one spot foxface. Also you can have a nice amount of fish, 10-15 depending on what fish you choose, (maybe even more if you are a nano fish enthusiast).
I felt I was able to create an interesting aquascape with the footprint of the 75g.
The equipment on my tank is basic and I am relying more heavily on biological function for filtration; a sandbed with part of it being deep, and mature live rock.
I have an oversized Oase BioMaster canister filter. I have had sumps but I love the safety and simplicity of a canister, especially this canister. The BioMaster has an integrated heater so its not in the tank and it also has a prefilter that can be rinsed without opening the canister. In the year that I have had it, it has not disappointed me.
My tank is not the showcase that many of the tanks on R2R are, but its still nice.