All of the above is correct and incorrect. Confused yet? Welcome to forum life... Personally I like canisters. I get a much better turnover rate than most HOB waterfall type filters allow.
There is a prevailing opinion out there that canister filters are "nitrate factories". This, like most other elements in this hobby, depends entirely on YOU. IF you perform regular cleaning of your filter, the "nitrate factory" opinion is a simple myth. The issue arises when you fail to perform your scheduled maintenance. If you don't clean your canister on a regular basis, it will most definitely become a "nitrate factory". This is true no matter which way you go! ANY filter, if not cleaned regularly, will collect detritus and allow nitrates to build up.
For what its worth, I use a canister on my 55G tank and have for decades when it was freshwater tank. I have found that it clears the water column much more quickly than any HOB filter could hope for.
It all boils down to this simple question, which only you can answer. Are you willing to add an extra 30-45 mins to your maintenance schedule to clean your mechanical filtration in your canister? I actually bought 2 full sets of replacement sponges for my canister so I can simply remove and replace them easily and save myself some time and effort.
Cheers,
Steve