All I have heard about them is nothing but praise over on Instagram and a bit of praise in the CGC thread. I personally haven’t used the grading service. From what I have heard and seen the turnaround time is fast.
I usually use a middleman service for PSA & Beckett for grading.
CGC seems pricey with the shipping part of it for where I am in the world. I don’t have access to Fed Ex and I am not overly comfortable sending via Auspost internationally at the moment.
It would be awesome to try them out one day though. I do like the look of the cases and the labels.
Might be a good idea to check out the CGC thread like Zorloth suggested,