I think cleaning a HOB is quite a bit easier. However, I found myself cleaning them once every week or two, depending on the conditions of the aquarium, stocking, etc. Cleaning a canister takes about 2x them time and effort. However, I may clean it 3-4 months and it's not really in need of cleaning. At 6 months, usually just takes some time.
As Mizuhuman said, cleaning the tubing can be a pain but I don't do it more than once a year, maybe 2 years. I do clean about 1/2 the outflow and the entire inflow much more often but that is only because I take that section off to clean my lily pipes. It's easier to just clean them when I have them off.
Anyway, my point is it may take a bit longer and more effort to clean a canister but you do it way less often so ultimately, I find a canister easier.
One other thing to consider. With a HOB, even a large one, you really don't have much room for more than 3 types of media or so. If you want to double up on your bio, you loose a place to put purigen, for example. In a canister, not the case. Plus, you can put in an inline purigen reactor, inline heater, inline co2 setup so that is something to take into account. They are more quiet. I have to use about 2.5x more CO2 with a HOB as well. Minor evaporation can be an issue in a highly planted tank as well.
Not trying to knock HOB, I think they are great for the right type of tank. The main reason I use canisters on my low techs are they are usually in bedrooms which can be annoying to people, especially myself.