What kind of SE Asia location are you interested in?
Hyatt doesn't exactly seem to me as a major player in the region, and none of the properties strike me as those exceptional ones that we all strive to redeem our points for. Of course, if you have a specific property in mind, it might make sense then.
I never stay at SPG, but I'm fairly certain they have excellent properties in Thailand. Usually I scroll through their properties when they have a sale and see a bunch of expensive beach-front properties that I would like to enjoy with my girlfriend.
There's IHG too - planning a week-long stay later this year at the new IC in Samui on points.