I have tried a couple, but don't really use them anymore as most of my work comes by word of mouth now. I feel my builder is the best of the bunch, rated people is total rubbish as leads expensive and no contact with customer before money is taken. check a trade is a joke and in my opinion should be fined for misleading adverts as their rep was selling it to me by saying once you have joined get all you friends and family to write a review. there adverts are selling the this site for genuine customer reviews I feel it is misleading that anyone can write a review for you on there without having to have had you carrying out any work also this makes any figures the rep is selling you to encourage you to join false as you can not tell if they are genuine or not. But on the other hand I do know People on check a trade and they say they do get bit of work from it.
I feel my builder is the best one as you get a small amount of contact with customer before money is taken and also there jobs are cheaper to buy than the others, and a transaction has to be made before a review can be written which I feel makes the site better for customers to find genuine good tradesman.
Although obviously there is still ways around this to get yourself good reviews out of the ones I have used I found this the best for me, but word of mouth is always best advertising.
Hope this helps