if you buy puts (or calls if you're short), you pay premium and can lose it if the underlying goes in your favor. That's the drawback. The advantage is that you participate in an upward movement if you get past a certain point in the underlying--the breakeven.
long 1000 shares of SPY at 100
long 10 puts at 8.00 K=100
if SPY moves to 90, you lose 10 on SPY and gain 2 on the puts. Net loss of 8, instead of 10. At 85, you have the same 8 net loss on SPY, so you are capped on losses. As far as the upside, there is no cap there. SPY at 110, you lose 8 on puts and gain 10 on SPY, net gain of 2. SPY at 120, you have a net gain of 12.
With futures, the hedge is close 1:1 if the notional amount is the same. You don't expose yourself to losses, but you don't get gains either. Unless you hedge 1/2 or 3/4 or x/y, then you have effectively sold the underlying while the future is in place.