The answer depends on your personal situation. Both are essential for a long term portfolio.
Provident Fund or PF gives a good tax exempt growth and should be a core ‘debt’ part of your long term portfolio. A good set of direct mutual funds should also be in your portfolio for inflation-beating growth.
I have personally invested heavily in both and have ‘peace of mind’ of having a stable PF corpus while getting good growth from Equity Funds.