I am a regular user of paytm. As far as recharge services are concerned, I can easily say that paytm is still one of the best provider in market.
But since the introduction of marketplace in paytm, the authenticity of paytm gets decreased drastically. As anyone can sell over paytm, which make it new eBay of Industry. Its really hard for an end user to trust an outside seller.
The paytm should take some quality measure to ensure the correctness of product. I once got a duplicate mobile cover from paytm. Since then I stopped buying things from paytm and now I am using it for recharge only.
Website is very interrative though and paytm comes with lot of offers also but product authenticity is the biggest question that Paytm has to deal with in near future.