For those of you that are trying to decide between one of those pop-open beach shelters and a product like the Kelty, this is the review for you. I decided on the Kelty Medium Sunshade and just test drove it for a week in Florida. While those with the cheesy pop up shelters were chasing them into the surf or propping up side with beach chairs, my infant son, wife, mom, dad, and me were all snug under the bomber Kelty sunshade. I put a stake in each of the corners for good measure, but realistically didn't need it. I can only imagine the type of wind that this thing would hold up to if the 6 guy points were staked out as well. Have not had it in the rain yet but assume that it wil perform there too. The medium is BIG. Enough to cover a standard patio table and chairs no problem. The only advantages to the large would obviously be more coverage area and more clearance when entering--you sort of need to duck to get under the medium, but once inside, there's plenty of room to stand up straight (I'm 6'). Great ventilation. Less than 5 min. to put up, less than 5 min. to tear down. Bomber.