I have seen those before, but this is the first one where I feel they did everything right from a users perspective:
What makes them different is that they are more than a review database. They compile the expert knowledge about how to deal with contractors and lead you through a well defined process. I.e. when I was researching house cleaning it got quotes for me from three companies and outlined all the steps of the process (first contact, get quote, …, give review feedback) so I knew what to do next. The user interface is super intuitive and they provide exactly the information that you need where you need it and when you need it.
Their email followup that leads you back to the review a week after the job was done is unintrusive and helpful.
They do try to re-engage you and propose other services you might need while you are on the website and completed giving your review, but instead of being an obnoxious upsell attempt they actually do it in a way that they provide value to you. I.e. they have articles about what you might want to look for beyond cleaning the windows when you are spring-cleaning and give you a very terse checklist where each item is worth considering.
In short I love their service and will use it again.