Especially common at Riverwalk are bowed doors that don't close properly. The hard lesson learned in Riverwalk is that new-construction homes are not bullet proof just because they're new. Consider hiring an independent home inspector to inspect the structure and systems for any problems or defects. Then discuss the report with your builder. Don't buy it.
Any builder has a contractual obligation to deliver the home free of serious defects.
And any builder who's serious about maintaining their reputation should resolve any flaws to the customer's satisfaction. Remember that the squeaky wheel gets the grease. It may take weeks of persuasion and several visits to the site. You may also want to ask about warranties while you're still shopping around among builders or developers. In the past, home warranties have earned a reputation for being almost impossible to collect on.