Hi,
LOL...I call those who hate canister filters...sump snobs.
Properly maintained, they are absolutely not nitrate factories. All filtrating has one goal...to help break down the nasty stuff to nitrates, and then it is supposed to become a harmless gas to evaporate...but that last part takes way too long for our tanks, so we do water changes, or have macroalgae, or scrubbers to absorb it.
I ran my very successful reef for 14 years using two canister filters without a single hic-cup...my nitrates were always around 5 to 10. When I switched to the sump...exactly the same thing. The only time I ever had 0 nitrates, was when I went to seahorses and kept macroalgae in the display.
Don't misunderstand, sumps IMO are still the best choice, it adds water volume, hides ugly equipment, and allows for a refugium chamber (worth it's weight in gold). HOB filters cause lots of salt creep, but are the easiest to maintain, canisters are good, not only because of the media choices you have, but that spray-bar is also worth it's weight in gold. I'm not sure about wet/dry, to me they are just sumps with bio-balls, I never used one so I really don't know much about them.