Yes, UA svc not very good, but UA miles accumulated thru other methods (other than flying) is counted for FFP status as well. You can redeem mileage to fly on other Star Alliance airlines... SQ is part of Star Alliance.
UA mileage redeem has certain blackout period, eg Christmas, Chinese New Year, Easter. SIA mileage redeem has no blackout period, ie you can fly any time of the year. However, SIA requires more miles to redeem for the same journey.
UA mileage redeem has certain blackout period, eg Christmas, Chinese New Year, Easter. SIA mileage redeem has no blackout period, ie you can fly any time of the year. However, SIA requires more miles to redeem for the same journey.
SIA has 15% discounts on the miles you need for redemption from time to time.
SIA requires less miles for Asia flights in general compared to UA ( and other Star alliance/Oneworld, I did a comparison between the various FFP to see which one I rather sign up ), but UA long hauls redemption ( trans-pacific, flights from SG-Europe) is better.
I keep one with StarAlliance, another with Oneworld, useful in different times..