Hi
I didn't use a company to do the snagging for me, not that there was lots of snagging.
It seems to me that the response from the builder is what matters, if they don't respond what clout is a snagging company going to have?
Guess you have to make your own mind up with the info you get from others and any detail from the company.
Hopefully there won't be too much snagging anyway.
Good luck.