We've used Angie's list and have done very well. We moved to a new area and it's not always easy to get recommendations. We do look at Yelp reviews in addition to the list.
We typically have 2-3 contractors/service people come in for proposals based on the better reviews. In the past 12 months we've used 7 services including electrical, aluminum, carpentry, painting, closet organizers and upholstering and all have been very good.
We posted reviews stating the pros and cons, as it is helpful to others just as it was helpful to us.
Luckily we are 20 miles from a good sized city, so there are plenty of companies on the list. It would not be a good service if you are in a rural area.
My 2 complaints are (1) that you have to pay for each area. In the process of moving we owned 2 homes and I had to join twice. (2) is that the medical reviews are a separate list, also a separate fee.
Added: I have given negative feedback on a couple of contractors with whom the proposal experience was poor. They are all still on the list and no one has rebutted them.