I've used Step2 for several years now, and have only scorched where I have accidently dumped the fertilizer. On the recommended settings (Scotts Edge-Guard Mini), I've never had burns from it.
We do spot spraying of weeds, otherwise, and Spectracide to kill the grubs we seem to have in our lawn.
Scotts Weed and Feed is good too, but cost-benefit is an issue.