I have been using Paytm for about a year now. I came to know about Paytm from a friend who used to use this very often. I found it very amusing at first and decided to give it a try. Same day I downloaded the app & started using it. After few days I was in love with this app.
It is very easy to use whether you want to add, transfer or recieve money. Last year UI was not that great as it is now. Now you can find everything on the homescreen.
I use it as my primary daily financial driver, I use it wherever and whenever I can. Now a days even some of the tea sellers and Rickshawwallahs are accepting Paytm which comes very handy when you don't have enough change for a cup of tea or a small Rickshaw ride to home.
It is also very secure. I didn't notice any kind of fishy activities by Paytm or anyone scamming me for money using Paytm.
The only drawback to paytm that I can think of is that even today not enough people are using it, sometimes they don't know how to use it and some people don't trust Paytm like wallets. There were also same news about people getting scammed by Paytm. Therefore it's advisable not to put too much money in Paytm, only keep money to get you through your day.
Finally I will say I like this app very much and anyone who wants to make his daily money transactions to be headache free and doesn't want to argue with vegetable vendor for change then this app is for you.