Which is the best telecommunication company for a 2-year contract plan?

Currently, I am under Starhub previous plan of XS, student version so, it is a 3GB + 1GB at $48. Now, my plan has reached the end of the contract plan and I have to re-contract to the new plan, how I sitting on the fence, whether to stick to Starhub or change to Signtel. I have 6 plans under my name, all are due for re-contraction at different timing. I have a 30% discount as a hub club member. Does anyone of you have a comparison of both 2-year plan and sim only plan for Starhub and Signtel?