I reviewed a contractor on Yelp! It was accurate and did not reflect well on the contractor for the work he did. I did give him 2-Stars because, as I explained, when he did put the 22 foot gash in the floor, he immediately owned up-to-it, and said, "I'll do whatever it takes to remedy this". And I explained in the review that the reason it wasn't a 1-star review and is a 2-star is because he admitted his mistake and contacted his insurance agent that day.
My "negative" review wasn't just about the gash made by pushing a new stove across it, it was about the way in which the work was performed. Some was good, some was a bit shoddy, and the gash was just stupid.
So, go ahead and tell the truth. Do not embellish. Generally, with contractors, there is no reason to.