I have successfully used this service and would consider it again. However, I am dubious of all these reviews because they use the same language "contractor" which says to me that they are trying very hard to be sure that we know that this company is in the scheduling business and that they are not responsible for the quality or results. Secondly, they keep mentioning a tip in a specific dollar amount. Hardly subtle.
You said you have successfully used this service and would consider it again, so why do you think positive reviews are "dubious"? The positive reviews are all real, but some of the negative reviews are fake, left by contractors that were removed for taking orders but not finishing them.