I always try to book direct with the hotel using AAA discount or whatever I can do to lower the rate. However almost every single time I get a cheaper rate booking third party though priceline or hotwire. Example, I was able to book the Westin Nanea Ocean Villas on Maui for $210 per night a couple weeks ago. The direct booking price was $459 per night. At check-in my room was upgraded at no charge. Most hotel frontline staff could care less how you booked your room or what you paid. If you are genuinely nice to them you have decent odds of getting an upgrade.

Just another data point, I stay in Albuquerque for a couple nights monthly on business and have been doing so for the last three years. I typically book a room direct with a hotel I want to stay at, then a couple days before the trip search third party sites. Only one time in the last three years have I not found a significantly (20-40% off) better price through third parties. Granted with Priceline and Hotwire they don't tell you the exact hotel you'll get, but it's not hard to figure out ahead of time based on rating and amenities.

The hotel price match guarantees have been a joke in my experience and a huge hassle. I tried to get a hotel in Vegas to match a third party site. They verified everything, but then denied the price match because the deposit terms for the room were slightly different. Once again booked with a third party site, got upgraded to a suite and had my resort fees dropped by the front desk staff.

I truly would like to book direct with hotels, but I have yet to see an advantage that outweighs the savings I receive booking third party.