While I do not think one is better than the other, I do personally enjoy trade hubs much more. Simply because of the fact that from personal experience, trade hubs seems to provide a much more social experience in the game. Meeting the contact agent is rather interesting and intriguing. It's like going to the store and being greeted with great customer service.
I personally like customer service because often times I do have a few questions or concerns about a product or service. Though, I realize this may not be the case for everyone, there are many who just simply wish to purchase an item and quickly move on to other things. Which is what I like about auction houses and the fact that they help remove in-game gold.
But in all honesty, I don't think one is better than the other, at least not in an economical sense. Really having an auction house or player-made trade hubs/housing is mostly about personal preference. None of the decisions will make or break an economy, simply because whatever choice is chosen the market economy will pretty much adapt.