Citi transfer to AA is probably the most useful partner now!

Strata TYP can transfer to AA - one of the only 2 can do that, this and the Bilt card.  This already makes it far more useful than other cards due to UA has devaluated SOOOOO MUCH.  Example, AA (or AS for that matter) 60K Japan - US, UA wants 110K on partner 100K on its own matal, and ONLY when you have a UA CC.  EU-China, AA is 75K even via DOH, UA is 140K!!! 

You have to think about airline redemption in the concept of Alliances.  Far more often than not, it is much better both in terms of aircrafts / services and cost, partner flights vs the program's own metals. 

Plat sign up bonus I have seen 150k AND 250K (pop up window when I logged in AMEX) and reportedly there is 300K but of course the spends are also in 10K or more to earn that, though in 6 months.  Though I am not interested currently, until my current balances have been spent down.

Have you used blogs like the following?  Both have tabs on latest Credit Card SUB

https://www.doctorofcredit.com/   and   https://frequentmiler.com/

Chinese blog

https://www.uscreditcardguide.com/zh/ 

and the related discussion forums  (click the tab on the far right top)  - it does require certain knowledge / understanding, to figure out what they are talking about - most are taking advantages of loopholes, being this is a site for Mainland Chinese who work / study in US/Canada.  I am sure you understand how this would go...  So if you use any of those tactics talked about, it is at your own risks.

https://www.uscardforum.com/?utm_source=uscreditcardguide&utm_medium=menu&utm_campaign=uscreditcardguide_menu_link