I stayed there last week, for the first time in their "new" wing. It is an acceptable Hyatt, nothing special. No RC, but they have almost always upgraded me to a suite.
I think Irvine is a better property, but it depends on why you are there to begin with. We use it to take the kids to Disneyland, and they have a free shuttle every 30 minutes. This saves about 40 minutes roundtrip, as if you park at Disneyland, you have to take a tram to and from the park anyway (and pay $8 for that pleasure.)
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United UGS, MM
Hyatt Lifetime Diamond
Starwood Platimun