Yes, Zebpay App is a good app comparative to Unocoin. But, I feel that the price is higher than other sites. App-wise Zebpay is the best in the store, but I wouldn't suggest the site for trading. For trading you can go for Koinex, Coinome or Coindelta
The higher price among all the exchanges I think is of UNOCOIN. They charge the highest fees also and their spread between of buy and sell sometimes goes with a difference of 1lac. Not sure now much business does Unocoin does with so much competitive market where their exchanges fees are less and prices are better.