I have the normal sbi card since abt 4 years. this card also offers the same railway offers that the railway credit card does. so you need not get a railway card. also the value of holding an sbi card is also good. if you want to apply for any other card or a loan in the future you can easily get it on the basis of an sbi card. cause most other banks consider a person holding this card to be genuine & secured.
even when ive wanted a loan or any other credit card, ive got them just by giving my existing statement for sbi card. other banks tell me that sbi card is given only after a long verification process & only genuine good income holders pass their test.
regarding the service, its pretty ok. I have atleast 5 different credit cards & I would rate sbi as the best.
though its very difficult to get a raise in your credit limit & also there are relatively less freeebies. but most other credit cards like stan chart, abn amro, hsbc are always trying to con you into paying more... but this is not the case with sbi.