Many folks have been damaged by UG filtration because they were not taught how to maintain them. An ignored UG is a time bomb. But so can an ignored HOB or canister filter be such, or simply under-maintained substrate can do the same. All tank components require care - if properly handled, all formats of filtration can do the job. Improperly handled, all can be major problems.
I love the folks who claim that UG is antiquted tech - Canisters, power filters, and UG all came in about the same time (I was in the hobby already then). Wet/Dry filters popularity came later, fluidized beds later still. All the first three were based on changes in the pumps available to the hobbyist. All have developed technically. UG has been the most misused and misunderstood, and unfortunately it still is.