It's excellent until you realize that you're paying WAY more for every click than you would with AdWords and that their reach is only limited to Yelp and doesn't do THAT much to boost your presence. My mom was considering it for her daycare business but I argued against it for this reason and many other small businesses that have dealt with them concluded the same thing.

yup, same here. I help SMBs with marketing, and Yelp is usually never worth paying for.

The only small case is when the ROI on adwords is reaching the level of diminishing returns

So does Google :)