I can't speak for GAL, but I know Universal Gemological Laboratory is! I've had a few of my diamonds appraised there and they are great! The work is done right infront of you and they answer any and all questions you may have. I say give them a shot if you need to have jewelry appraised.
Here's the lowdown on each of these places, GAL and UGL. GAL's owner and UGL's owner are related, GAL's the uncle and UGL is his nephew. They were together until there was a fallout between them that's when the nephew started UGL. GAL is now primarily run by the owner's son, a GIA graduated individual who wants to think he's running his ship like they would over in the GIA lab but he never took advice from anyone who's actually WORKED for GIA. So, he doesn't know. His experience is limited and I understand one of his equally inexperienced classmates is there to help him. The one person that made GAL reputable has started his own business and I wouldn't hesitate refering people to this guy.
Reputable is an expression that says a company's got some good history but it doesn't say that it's a good place today. In my opinion GAL's "reputation" walked out the door a while ago and they're still riding that reputation to save the sorry excuse of a diamond grading and appraisal lab it is right now.