I wanted geese to weed - but they have since become lawnmowers . . . don't know that I would trust them to weed anything very important - even if they don't like to eat the plant, they still will chew on the plants - they aren't supposed to like evergreens, but every now and then they decide to munch on my fir and spruce trees. . I know I read about them weeding potatoes and corn fields, but I just have trouble seeing that it would work out well. They also leave many of the most common, annoying weeds - so I'd still have to go through and pull out the ones they didn't like . . . All geese love grass though, and they excel at keeping grass shorter, plus fertilizing it. The areas where the geese live have grass that looks like it grew on a golf course . .. .
My American Buff geese are quiet, and friendly, and most are pretty tolerant even during the breeding season. The neighbors can drive in / out of their driveways, and move around their yard, without my geese having fits - a good thing for me and for them! Mine have all made nests and gone broody although not all ended up with goslings. I've also heard good things about Pilgrims and they have the added benefit of having different colors for ganders and geese, so they are easy to tell apart.