Apples and oranges my friend.
You cant compare on a one to one basis like that because the underlying asset is different. On one hand, you have a fixed income product (PPF) and on the other, we are looking at a market denominated product and that too equity (I trust you are asking about an equity fund).
See, its very basic. I am a firm believer in the ability of the equity markets to return above than mean returns over a longer time horizon. If you are positively predisposed towards the equity market over the next decade or so, then you should be in SIP. Plus, because the valuation of units is at current levels and we all know how the markets are, so your entire investment is valued lower. However, in the coming days, these are the units that will get you a bigger bang for the buck.
This covers the concept of SIP. The second thing is about the scheme or the brand, upon which I will not be able to comment.
My personal take. SIP is bound to provide superior returns. But with time.
Stick to it.