Vsp Providers Las Vegas Most Reliable Wireless Datacard Providers In Visakhapatnam & Hyderabad?

Most reliable wireless datacard providers in Visakhapatnam & Hyderabad? - vsp providers las vegas

"I am a software engineer for travel in India (Andhra Pradesh) in the next month and is scheduled to wireless data (Internet to connect) Maps (via VPN) to my work systems (USA). I heard that Airtel and Reliance provider of wireless data cards are popular and others have said, BSNL good in HYD and VSP.

1). Who has a better provision (BSNL, Tata, Airtel or dependence), Hyderabad and Visakhapatnam?

2). Is it necessary to order in advance or can I get a connection, the same day, if I have to register?

Thank you for your help.