I am a regular shopper from Big Bazaar and I am glad that a new store has popped up just near by house at Mumbai Central!
Big Bazaar as its claim: "Isse Sasta aur Accha Kuch Nayi" is not very true. You will definitely find Apna Bazar and Subhiksha much quite cheaper and as far Achha is considered, I guess the qaulity is not up to the mark.
Ofcourse for shoppers its a boon as all of the months household shopping can be done under one roof and they do home delivery too in some cases.
My only suggestion is that you have to be be careful while shopping from BB, as at times the offers that are displayed on the shelf are not updated in the systems as result you at times do not get the discounts / freebies.
Big Bazaar will have to improve the quality of their staff personnel too.