With firearms stores, most of these have to do with the people working there and the procedures they have to do.
One LGS is a small store with a good used inventory, but doesn't treat window shoppers too well. It's definitely a not a place to waste the salesperson's time if you're not going to buy something and I have seen some gruff interactions. However, this place is one of the best buying experiences. Prices are competitive, you get a cash discount, and once you say, "I'll take it," you're handed a 4473 and a pen. They call in the NICS check immediately and a buyer is out the door very fast.
OTOH, my worst buying experiences have been at a certain big box outdoor store. I even ordered online and already paid for the gun. The store calls when the gun is ready. I have to take a number when I arrive at the gun counter and wait for every window shopper ahead of me. OK, I can wait my turn. Once the salesperson attends me and prints their paperwork, they direct me to a computer to fill out the 4473. I wait to clear the background check. Then, they have to get my firearm out of their locked storage. However, the first associate cannot find it. They look again - can't find it. They look behind the counter - not there. They call the manager to look for my firearm. The manager finds it in their storage location. I've passed the background check, fill out the store's paperwork. Finally, the manager has to be called back to review everything and that I have actually paid for the firearm. I am finally escorted out of the store, with firearm in hand.
The process from the time that I was waited on to walking out of the door is an 1-1/2 hours. Remember, that is for a gun that I have already bought - no shopping time involved. The first time, I thought it was just an isolated thing, but after another buying experience, it appears that the 1-1/2 hour time frame is the norm for their processes. Sometimes a deal is worth the wait, but it has to be a really good deal, especially in comparison to the 20 minutes maximum at the first LGS.