Sterling projects are usually at good location and premium priced. Quality I would stay is relatively better than many tier 2 builders. But when it comes to sticking to schedule, they are not even comparable to tier 2. Assume at least 2-3 years of delay. You ask any project of them, and resident they can confirm.
Some other points -
1) They do small small changes to save money, giving some reason(architectural, structural, .) to save money, infact their layout and elevation plan will show all that, I used to think that all that architectural plans and structural decisions are taken before finalizing layout and elevation plans.
2) They have some issues with SBI bank, most of the time they force you to LIC. There property though always approved by SBI, but they always force you to go with LIC if you want to book, at least in later booking.
3) Delay is the worst thing with them, they cant even come up with good reasons for delay. Some of the common reasons they give like - labour shortage, sand strike, material procurement . common you are running a business and these are the risks you have to mitigate and manage, how could you pass all the results of your worst management practices to owners.
4) They will tell you upfront that in sales document they will not change even a single word.
I am not saying that you should not go with this builder, but be prepared for good delays.