YYZ,
I would HIGHLY recommend staying at the JW. It is one of the most beautiful Marriotts I have ever stayed at, but I can't say I've ever stayed at the Hyatt in Vegas to compare, but I like this propery more than Bellagio.
I tried dates Aug 7 - Aug 14, and found the following for you
If you are a
VIP you get the room at $135
If you work for
PEPsi $143
GMC $143
ATT $143
If you work for
GOVernment $79
If you belong to
AAA $143
If you want to come out and play
OP7 $159
Hope this helps.