State Bank of India is a common mans banker and of course the largest retail banker in India. It has a vast customer base owing to the fact that it is owned by the government with a majority share holding. It has much more branches and ATMs when compared to any other bank in India. This factor makes it a leader in banking sector as it is easily accessible.
They offer almost all features of banking that are made available by private banks and at a lesser cost than such banks. But they have to improve a lot when it comes to customer service and support. In case a problem arises with a debit card or if you want to apply for a new check book, only God knows when your complaint will be resolved. I have applied for a new ATM card and was made to wait for a solid 30 days. So if you are looking for a faster service SBI is not your place.