I actually love Trip Advisor - I think it's good to get real-world accounts, and not just Disney fanatics (a nice mix helps). I use Trip Advisor all the time - it's how I found the Bed and Breakfast I'm staying at in London right now, and the hotel I'm staying at in Paris starting tomorrow (we stayed at both in September as well).
If there are a lot of bad reviews for a hotel, I tend to look elsewhere. From what I understand, people who either love a hotel or hate it will be more likely to post on Trip Advisor. There isn't as much grey area. I always feel it's my responsibility to write a report every time I stay somewhere recommended by TA.
That said, I've not seen the BW reviews. There could certainly be some rooms that aren't as up to snuff as others, just like when some friends of mine showed me the laundry room at the Y/B resort, the door is rotting there. Not everything is perfect. Disney still does it better than most, though!