The past three trips its worked well for us. They new our room request and we've gotten the building that we requested.
Works great for us but we are Premier. So dont know how it works if not. But several have posted thier experiences.
We always do the express check in, no proof that it has helped though. Only once did we not get the room category we paid for (out if 11 visits) and that time was last Sept. (soft opening and only a couple lush suites were actually finished) in that case they upgraded us to master without being asked
Last trip they read the notes from my express check in and said sorry we can’t meet your request. I was asking for a higher floor for the master as they have bigger balconies. So it showed me they do get them and they do read them but not quite confident it will result in anything productive.
I just hope it keeps us from having to fill out the same information as on the check in. Hopefully its populated somewhere to save some time. Guess we will find out soon!