If I'm a buyer, should I find my own real estate agent or have the listing agent as my representative?
You should definitely get a buyer's agent. The listing agent has a fiduciary obligation to his client, the seller, and must work for his best interest. You will be at a great disadvantage if you use the listing agent as your agent.
Besides, there is no cost for using a buyer's agent. Some people think that the seller will give them the commission if they don't have an agent, but it never works out that way. They may lower the price by that much, but they probably would have lowered it that much anyway if you had an agent. There's just a million ways that you can be taken without competent representation - it's like going to trial with out a lawyer. In your case, ask youself this - would you let the prosecuting attorney represent you as a defendent?
I can only speak from experience from real estate transactions I've witnessed in Texas. A listing agents duty is to the seller of the property. They must disclose any defects with a sellers disclosure, make suggestions on fair market value by comparing it to similiar propeties in the area.
Their main goal is to get the home sold and to represent the seller. If they represent the buyer as well it is hard for them to negotiate both sides equally. As a buyers agent, their responsibility is to negotiate the sales price, closing costs, and make sure the buyer is getting a fair deal. I would recommend that you search out a seperate real estate agent to help you with this purchase.