I've purchased several guns from J&G Sales. But none were online. All were walk in buys. Davidson's is my go to distributor, first and foremost. I've bought countless guns from them. You cannot beat their Lifetime Free Replacement Warranty. I used it once and had a new gun in my hand in 24 hours. No other firearms distributor in the country provides that. They are literally the "Craftsman Tool" of the gun industry. And as they say about warranties, no one cares about them until they need them. They also ship very fast.
I purchased one gun from Brownell's, and the transaction went smoothly. I would buy from them again. I've heard good things about Palmetto State Armory, except for their shipping. They can take forever. I've never dealt with Bud's, but I would have no problem in doing so. They move a lot of guns, and have excellent prices.