I wish I could see the video but no link was provided. I searched a while myself with no luck. In any case I looked into the manufacturer of the clothing and they adhere to National Institute of Justice or NIJ standards for ballistic protection. Since that's the case, they wouldn't have to use "low power" rounds for demonstration purposes. Also, observable recoil isn't a reliable way to judge the relative power of any cartridge since experienced combat shooters make recoil appear nil due to superior technique. Likewise, new shooters or those will poor technique can make recoil appear atrocious.
Soft armor comes in 4 main certified categories, I, II-A, II, and III-A, from least to most protection. Level I is rarely worn and isn't allowed by most police agencies or recommended by manufacturers because it doesn't provide enough protection again typically encountered calibers. So basically there are only three commonly used "soft" types, II-A, II, and III-A. Level II-A will stop 9mm FMJ at 1,090fps (332mps) and lesser calibers. It will also stop .357 Jacketed soft point at 1,250fps and lesser soft point calibers.
Being that level II-A is the very minimal norm there are typically three types of fiber/arrangements to attain this level, 6.0mm of standard Aramid fibers, 4.5 mm of Premium Aramid fibers, (very common) or 3.5mm of Ultra-thin Gold Flex. While slightly more powerful calibers can be stopped by level II-A the limiting factor is usually blunt force trauma. Any greater deformation than 1.7" or 44mm into soft clay media behind the vest and it fails NIJ standards for that class. Steel, carbon fiber, or an additional layer of soft armor trauma plates lesson blunt trauma but they're not counted toward the NIJ resistance rating. The only way to attain the higher rating, in this case, level II, would be to move up to a level II rating, which means more weight and bulk. That's 7.5mm of Standard Aramid, 5.5mm of Premium Aramid, or 4.0mm of Gold Flex.
There are many different body armor types in development or production, like Dragon Skin, or Shear thickening fluid but when in comes to certified soft fabrics, like the kind they're using in clothing, there will be a minimum thicknesses of 3.5mm level II-A, 4.0mm level II-A, and 5.25mm in level III-A. If they're showing you examples of any Aramid or Gold Flex fiber that are thinner than this, they're not being straight forward with the audience. For example, the sleeves, shoulders, sides, and lower belly of a shirt may be a standard cotton, while only a 5" X 8" sternum sized area is protected with NIJ rated ballistic protection. Well, this is extremely marginal and no LEO would be caught wearing something this minimal. A level II vest with clamshell front and back protection with open sides for ventilation, made of Ultra-thin Gold flex is going to weigh about 3.5 lbs. This is typically considered minimal body coverage and minimal multi-threat level protection by LEO and body guards. A stylish jacket in level II, without sleeve or over the shoulder protection but full-wrap torso is going to weight 5.5 lbs at the absolute minimum. So, if they're showing you lofty, blowing in the wind type materials in their demos, they're being slightly deceptive. Judging by their website they disclose these limitations but it's not until the point of sale that the average person is going to know that there's a bulk and weight penalty to pay for ballistic protection.
Lastly, none of the soft armor discussed here will provide reasonable stab or spike protection. A good quality knife or spike will go right through soft armor without too much trouble. I stabbed though a static level II ballastic stack sample with a common Benchmade AFCK, with about 50mm of penetration into cardboard backing.
An ice pick buries to the handle!
To deal with this manufacturers are adding stab resistant inserts or SRI's. These are rated in level 1,(24 Joules) 2,(33 Joules) and 3(43 Joules). There are also over-pressure ratings of 36, 50, and 63 Joules but this allows for 20mm of "over-penetration" meaning that the wearer would receive 20mm of penetration into his body. Even level 1 stiffens up the armor significantly though and they are not as comfortable as wearing soft armor alone.
I became interested in this subject many years ago when an acquaintance claimed a new material for use on passenger luggage to provide ballistic protection. I was given two square feet of the "secret" material for testing and it turned out to be a joke. Not only did .22LR at 1,050fps penetrate, but so did .177 caliber soft lead at 650fps. :laughing: Through this process of researched I eventually informed my acquaintance about NIJ standards and Twaron...I don't think Gold flex existed at the time. Eventually I worked with a guy selling various types body armor at local gun shows, I own some of my own and have kept up with innovation ever since. It's actually very slow moving developmentally and hasn't been hard to follow over the years. There had been greater development in hard armors but trust me, no stock broker is going to wear that on his way to wall street. It's simple not practical.