I dropped all my other ads, Angies list worst 1k I ever spent for a year.
I would say if yelp is strong in your area and you have decent reviews it works.
I went from 10 to 12 reviews before I started advertising to about 24 reviews now and I'm in an area where there's no one with more then 10 maybe one company.
So I went from $300 per month for 500 impressions to $500 a month to 1100 impressions and the phones are ring, running 2 trucks a day 4 to 5 days a week.
With Yelpers you better give them your best and they'll reward you If not dont bother.