I'm with @
HomerJ!
As an SPG Platinum 100 Ambassador level guest, I've been able to enjoy a massive number of exceptional suite upgrades, even on mostly award stays, at some of the best and most aspirational hotels in the world. I've also enjoyed particularly good service at most SPG hotels at which I stay, even at those brands that aren't as known for offering particularly high level service.
I find it extremely useful to qualify for the Ambassador level service...and then continue staying with SPG hotels, especially whenever at SPG luxury level hotels like St Regis, Luxury Collection, and sometimes W, to enjoy the amazing Ambassador benefits. I see good recognition for my status at Le Meridien, Westin, and Sheraton, but they rarely treat me as well as the luxury level hotels--understandably!
My most recent examples:
St Regis San Francisco--heading in another week for 3 night paid entry level room stay, already upgraded to Metropolitan Suite (no SNA), allowed to bring 110 lb dog despite 35 lb weight limit
St Regis Houston--Dec 2017 just returned from 3 night paid entry level room stay, upgraded to Astor Suite (no SNA), allowed to take Plat breakfast with room service, called by name by valets and some front desk staff. truly wonderful service
St Regis San Francisco--Nov 2017 for 2 night paid entry level stay, upgraded to Metropolitan Suite (no SNA)
Prince de Galles Paris--Oct 2017 for 4 night award stay for husband's bday, upgraded to Makassar Suite (SNA), provided exemplary service for us and bday party guests
Hotel Imperial Vienna--Oct 2017 for 3 night paid and award stays with mother, upgraded to Imperial Suite (SNA), mother upgraded to Elisabeth Suite, VIP piano concert comp'd tickets, truly outstanding service
St Regis Rome--Oct 2017 for 4 night award stay in junior suite, shown excellent service
St Regis Bahia Beach Puerto Rico--Feb 2017 for 3 night paid stay, upgraded to St Regis Suite (no SNA), comp'd Plat breakfast for room service
The Nines Portland--Aug 2017 for 1 night for paid stay, upgrade to the Nines Suite (no SNA), best in hotel suite
SLS Beverly Hills--June 2017 for 1 night for paid stay, upgraded to suite (no SNA), given f&b credit after disappointment with suite, unbelievable service, allowed to bring 110 lb dog despite 35 lb weight limit
St Regis San Francisco--Oct-Dec 2016 multiple paid stays and 1 award stay, always upgraded to Astor or Metropolitan Suites (no SNA), Aman like service and treatment
Excelsior Gallia Milan--Oct 2016 for 3 nights award stay, upgraded to Atelier Suite (no SNA)
Gritti Palace Venice--Oct 2016 for 4 night award stay, upgraded to Sestiere Suite (well above SNA), given comp'd Riva Excursion, truly world class Aman like service and treatment
St Regis Bora Bora--May 2016 for 6 night paid 3rd party stay, upgraded to Royal Overwater Villa (no SNA), given personal butler for entire stay, allowed f&B credit for unused 1 night non-refundable stay missed due to canceled flight saving me $2000, truly amazing service and treatment
St Regis Punta Mita--Nov 2015 for 5 night award stay, upgraded to deluxe suite (no SNA), amazing service and treatment
SPG obviously has been extremely good to us. We are very loyal to SPG and SPG is very loyal to us. We also occasionally have stayed at other top luxury hotels when appropriate (Amanbagh, Taj Umaid Bhawan Palace Jodphur, The Lodhi Delhi, Oberoi Udaivilas, Amangiri, etc), usually when the SPG luxury option isn't available or isn't comparably luxurious, so we have a very good perspective on what top luxury and extraordinary service really mean.
For 2018 we have coming up:
St Regis Punta Mita--Jan 2018 for 5 nights in villa for my birthday, combo of points and paid upgrade
St Regis New York--Mar 2018 for 2 nights paid, SNA applied
St Regis Atlanta--Mar 2018 for 2 nights paid
Prince Gallery Tokyo Kioicho--May 2018 for 3 nights award stay, SNAs applied
Suiran Kyoto--May 2018 for 5 nights award stay, comp upgrade to Premier Room already confirmed
St Regis Osaka--May 2018 for 3 nights award stay, SNAs applied
(also Ritz Carlton Kyoto for 2 nights)