Laurel is a reseller just like every other Mustang parts house out there. The parts they sell usually are the same source as other parts houses as well. Commenting on Laurel based on parts quality isn't really conclusive, they only have access to mostly the same parts as the bigger houses do. Scott Drake is Scott Drake, if you know what I mean.
When it comes to Mustang vendors, you have the big catalog operations that have the stability of an established operation that can issue you credits the same day. You have guys working out of their garage on ebay that have no real stability but may offer personalized service, as they are often Mustang enthusiasts themselves. And then you have everything in between in varying degrees.
Laural is one of those in-betweeners. Experiences will vary.