Family member of mine has done this. Received US Citizenship and OCI - is now working in India for the last year.
1. They are working with a fairly large company - no issues with accepting OCI as authorization to work at all.
2. They have income tax deducted at source for salary.
3. They are required to file tax return in India AND in the US. In the US can claim foreign earned income credit (upto $90,000 foreign income tax exempt) - and credit for tax paid in India so there is rarely a tax liability (except on investment income in the US etc.)
4. NO REQUIREMENT WHATSOEVER to REGISTER WITH LOCAL Police Dept. etc in India - you are for all intents and purposes a citizen of India (just have restrictions - like you can't vote, hold political office and no government jobs that are restricted to Citizens).
5. Registering with the US Consulate is not a bad idea - just in case...
Bank accounts etc. - stick with the majors (ICICI, HDFC etc) no need for international only (Citi etc. - although if you have US accounts with any of them CITI/HSBC and can qualify for their higher status like HSBC Premier or Citigold - it makes it quite easy to transfer money back and forth for free).
Good luck - and enjoy yourself.