Mainly based on a combination of location & room quality.
Never stayed at the Monte Carlo but TI is nice and the location is prime. If price isn't an option I'd even consider the Palazzo which is close by shouldn't be that much more either.
What did you pre-register as? Media?
I'm going out there with a bunch of friends and looking for something to do the night of sunday the 25th. do you work at the XS night swim?