If anyone invented a gutter vac that actually worked and saved time, I'd buy one. I do a lot of condo roof/gutter cleaning, and in many cases, the debris has to be removed by hand and bagged on the roof. Some of these buildings have fenced (and locked) courtyards in the backs, so cleaning from the ground with a ladder isn't an option, plus it's much more time consuming.
In other cases, I can just blow them off with a blower, rake it up, and bag it.