Just my experience here. I was struggling to find out how to generate some business in this economy. i had a lot of different companies calling me, Service Magic, Angies list, Yelp, etc. etc.
I think it really depends upon the type of area you live in. I do a lot of work in the San Francisco Bay area, the internet based companies are well worth it here. Only because the base population uses the internet, "Google" or "Yahoo", to look up everything. It is expensive though, so you need to do a very good closing on the sale.
Good thing is, all the contractors you compete against are legitimate. They have a license and insurance. So it is not necessarily bottom dollar type stuff. I am doing $300.00 a month in advertising leads with them right now, and generating about $6000.00 off of that. Like I said, it is expensive, but I am now starting to get those customers to return to me instead of Service Magic, and getting leads from those customers.