I’ve stayed at both. Checked out from my fourth HR stay this morning. The Hyatt Regency is fabulous. The comparison
to Hyatt Place is really far from reality IMO. I’ve stayed at plenty of Hyatt Places as well, including BKK.

The SGS is a very different property and I would classify it as a resort in the middle of the city.

That said, the new HR rooftop bar, Spectrum, the great breakfast, the external F&B venues in the HR building and the views, the amazingly attentive staff, bridge to the BTS, make the HR of a similar level to the SGS albeit business/city vs resort hotels.