As the President of ApexFlags.com, I personally have not flown this polyester-2 3'x5' U.S. Flag. However, this would be my assessment regarding it.
3'x5' poly-2 U.S. Flags are the strongest material, size, and geometric shape of all U.S. Flags. 3-feet high by 5-feet long is a 1:1.6 hoist to fly ratio U.S. Flag. A different ratio would be a MIL SPEC U.S. Flag which is 1:1.9 hoist to fly ratio. So what does the difference in the hoist to fly ratios do?
This is what I believe occurs: just as a longer bull whip has more power the longer it is: so goes the U.S. Flag. The longer 1:1.9 MIL SPEC ratio is longer then a 1:1.6 ratio U.S. Flag. As such in equal winds and equal hoist size, the forces at the end of the longer U.S. Flag will be greater, because it is longer, and therefore generates more force. These increased forces on the longer U.S. Flag result in faster material fatigue at the top fly end corner. Faster material fatigue, than a shorter U.S. Flag, because of whipping and snapping.
So why would the military "specify" a longer U.S. Flag, if it is going to tatter faster?
The reason likely is due to endurance. Yes a 1:1.6 ratio U.S. Flag will tatter less quickly: but it has less length in which to tatter away before the stripes become too short looking. Now for you and me, the winds that we think are strong are nothing to the wind dynamics of say a military vessel doing 30-knots into a 30-knot headwind for months at a time.
As you can imagine the forces on a U.S. Flag in this type of extreme environment is going to result in tattered flags. Tattered U.S. Flags which may need to remain flying tattered but still represent the United States proudly even though experiencing extreme wear.
So what occurs is that the longer MIL SPEC ratio permits a longer mast time because the longer Flag has more material to tatter off through the sheer tearing off of material in extreme winds over time.
So why is this 3'x5' poly-2 U.S. Flag, a great flag for you? Well if you are in a very windy environment, but not an extreme wind environment, than nothing can beat polyester-2 for material longevity. And the geometry of the 3'x5' 1:1.6 ratio U.S. Flag means that the stresses on the end of that polyester-2 Flag are less. The result? The longest lasting least hassle U.S. Flag possible, for just about everyone. This 3'x5' polyester-2 U.S. Flag here on this page is made by a 100+ year old American Flagmaker.
Here is a question, does the military "spec" polyester-2 material? The answer is sometimes. But for just about any U.S. Flag or Ensign flown from Navy and Coast Guard poles and masts, the material is MIL SPEC 70-denier nylon, or in 200-denier in the 20'x38' Battle Ensign. I can think of many reasons for this including the longer range visibility of nylon vs. harder to see polyester-2.
But certainly one big reason the Navy specifies 70-denier nylon is that: when polyester-2 tatters, it tatters bad. And in an environment like a navy ship where everything is going to tatter very quickly because of the extreme winds: then the military 70-denier nylon is best: because it is high tensile, but lightweight material, which is tightly woven, and then lock-stitches closely. The result is a stronger flag in extreme wind conditions. MIL SPEC nylon holds a fly hem in conditions where other Flags like polyester cannot. And then when the 70-denier nylon fly-hem does tatter in extreme sheering environments like the high seas: then MIL SPEC nylon tatters in small hard for the eye to see pieces. The result? When in an extreme wind environment, tattered MIL SPEC U.S. Flags look better then tattered polyester-2 Flags.
This is because polyester-2 can become a big tangled mess when tattered. A tangled mess which when wet and heavy and twisting in extreme winds, is very hard on hardware.