Never heard of them, just found an old thread where people asked the very same question as you do now.
imho, escrow service should be of higher trust than the person you are dealing with, and in this case, both sides seam to be unknown and untrusted, hence - i wouldnt advise to use them.
There's a bunch of highly trusted people here that are offering escrow services, it may be better to use one of them.
Here's the thread where they all are listed and discussed :
https://bitcointalk.org/index.php?topic=855778.0