Howdy Snaggle, I have the largest Scotts rotary they sell. Edge guard...eh, I think it concentrates fertilizer on the edge with the edge control on, I don't use it, but my lawn is surrounded by gravel and big rip rap rocks on the river embankment.
With 3/4 acre of grass I get tired of walking it at the same speed to evenly and properly spread the granulized fertilizers. I fertilize a lot. It is easy to streak lawn if your not careful and paying attention by either overlapping or not evenly covering. Also, occasionally you will need to clean the whirley bird spinner under the hoper that flicks the granules, or "Broad casts" them, fertilizer builds up on it and it does not broad cast well anymore and that will streak your lawn also.
They claim that there is a lot of contaminants in the granule type fertilizers, they say they have weeds in it. I still use it, but I have to spray weed killers because N. Idaho is the land of the wild weeds, "Not That Kind of Weed"!
So, when I spray the forbidden in "Canada" weed killers, I spray Nitrogen for a fertilizer at the same time.