Most of us go with canisters, especially when we are talking about tanks under about 100 gallons or so.
Everyone has their own opinion. I have yet to use a sump but it seems like a lot of people are able to run quite a bit more CO2 because of how much oxygen it adds to the water.
HOB filters are fine for me. The caveat with CO2 is you need to top off a lot or your CO2 levels will not stay consistent. You all will off gas CO2 but you reap the benefit or more oxygen in the water. I actually find I do better with a HOB in terms of fish, though I don't use them anymore, plants do about the same. Maintance is much higher though, I find I had to clean them every 2 weeks to a month.
Canisters are what I use but I am not sure they are my favorite. What I like about them is maintenance is less often. However, what I don't like about them is when you have issues with them, you don't really notice until it's problematic. I may get a random leak hear and their but its so rare I don't really think to check. By the time I catch it, it has been going on for some time. I am learning over time (5 years) how to catch things more quickly by listening to odd sounds but only now am I catching things fairly quickly.
I also have chronic surface scum in one tank, I can get it to go away but it will just come back one day and really badly. That is only on 1 tank, I don't know why. I thought it may be what is on my hands or something but it only happens in one tank, I had 3 with canisters at one time, only one had the issue.
I am on the fence about reliability of canister filters vs. other options. 1 has been ultra reliable. One has been more reliable than my HOB. One has had it's problems over the years. Maybe I just got one bad one.
I don't want to say canisters are bad, most of us use them and I have been using them exclusively on my tanks for a long time. I sometimes question going back to a HOB but they are ugly and take a lot of maintenance. That's why I am think sump next, kind of has the benifits of both a canister and a HOB in one, with added filtration and more water volume.