If you want star alliance gold quickly, sign up for the TK or OZ program if your fare gets at least 100% miles. Both these programs will let you earn star gold for 40k miles over the span of 2 years and you have an additional 2 years to enjoy the status which includes international lounge access and priority boarding when flying on other star alliance carriers. (UA requires 50k over the span of 1 year in comparison) SQ has some pretty good redemptions for international premium travel. UA has some decent redemption options but it is not the most rewarding. You could also try AC which allows for short domestic US/Canada flights for 7.5k miles one way.