Since India is going digital there are many apps are available for transfer money and pay for something. Paytm is used among most of peoples in India that is why I always use Paytm for payments and money transfer.
About the service, I never any problem in transfering money and making any payments. The app is very good.
If we talk about the shopping part of paytm they have very bad service of delivery product to customer. Except shopping use paytm for recharge, payment, money tranfer only.