Thanks for the help so far folks.
To answer the person who asked where I'd read poor reviews, various review sites (TripAdvisor and the like). Guess I should take some of the reviews with a pinch of salt!
In particular, there are LOADS of crappy reviews for Breakers Express (rooms not cleaned, towels never replaced, staff disinterested, noisy teenagers in the hallways until all hours of the night/morning, etc., etc.). Sounds like not all of you would agree with that.
Also many bad reviews about The Breakers (some of the cheaper rooms tiny and tatty and musty smelling, poor service again.).
Obviously, the extra park hour is a big bonus, but it's not essential to me as we plan to be at the park at least three or four days, so should still fit everything in! And like I say, I don't require palatial rooms or endless amenities, I just don't want to book into one of their hotels only to find when I got there that the room wasn't clean or I couldn't sleep due to the noise.
I would welcome your continuing comments on this, and once again, thanks for the replies so far.