The difference between Marlboro Red hard packs and Marlboro Red soft packs is negligible. It all comes down to personal preference and, sometimes, supply. The seasoned smoker will have found his preference and will most likely not vary from it. Sometimes a new smoker will waver in her choices simply because their store may be out of the hard pack or may be out of the soft pack.
Those who choose soft pack
A soft pack of Marlboro Reds will most often be found in a person's front shirt pocket, or in their rolled up shirt sleeve. People who like to be able to extract a cigarette quickly with just a flick of a wrist, like the convenience of a soft pack. The soft pack also takes up less space than a hard pack because, as the cigarettes decrease in number, the packaging condenses. So if you don't carry a bag or a purse, chances are you're going to go with the soft pack.
Those who choose hard pack
A box of Marlboro Reds will most often be found in someone's purse or bag, or even on their car seat. If you are carrying your smokes around in your purse or in your car, you don't want little pieces of tobacco falling out of the cigarette pack making a mess -- and you don't want your smokes to get smashed. The hard pack protects them better.
Taste difference
Someone who swears by soft packs will say they taste better than cigarettes in hard packs - just as someone who only smokes hard packs will say they taste better. There is no scientific evidence to back up either side, it all comes down to personal preference.
Size difference
Hold a hard box of Marlboro Reds up next to a pack of Marlboro Reds and you won't notice any difference in the size. They may be packaged differently, but they are essentially the same cigarette. It isn't uncommon for someone to refill an empty hard pack up with cigarettes from a soft pack. They are interchangeable.
Price difference
While prices may vary from state to state, price does not vary from hard pack to soft pack. They cost exactly the same. You may feel you're getting a better deal by buying the hard pack though, because you are getting a little more packaging for your money.