Just an additional historical note, as I used to live in Green Bay. This was originally an Embassy Suites, and then was a "Regency Suites" (I think) before Hotel Sierra, and finally Hyatt on Main. So, the building is physically exactly what an Embassy Suites would be like. I agree with the above reviews as far as service and upgrades go. I'd say it's slightly nicer than a Hyatt Place, but yes, don't expect a luxury hotel experience. The hotel seems to have struggled ever since the AMS insurance company headquarters moved out of the adjacent building (yikes, ~20 years ago maybe). I'm hoping it stays a Hyatt, because it's a great place to earn a stay credit when I'm home visiting family.
Also, the bridge construction is finished now, so if the weather is nice you can walk over and go to Titletown Brewing company or Hinterland, which are both nice microbrew type places. The Broadway area on the other side of the river is getting to be a nice area - farmers market, some chocolate shops, Kavarna coffee shop and some other quirky places. I'm glad that the bridge is open again to make these places more accessible.