I actually just crashed in this vest 2 weeks ago at Thunderhill.
My IG post after the crash, showing the damage to the vest and the rest of my gear.
My helmet barely touched the ground because the airbag deployed around my neck as soon as I hit the ground (I low-sided on an off-camber right, so I'm pretty sure I touched the ground briefly before it inflated,) but it kept my neck stable, and kept my head off the ground for the rest of the slide. As you can see in the pictures, the left shoulder of my suit took most of the abrasion, and while I slid on that side, it also eventually punctured the air bladder of the suit. Fortunately, after contacting Hit-Air, they let me know that this is repairable, which is costing me about $120 plus shipping to Japan. I walked away from that with a slightly sore neck, and after getting some parts for my bike, I rode the next day with no pain at all.
Do I wish the vest had better abrasion resistance? Sure thing. When I started looking for airbag vests, I initially wanted the Helite Race vest, but after trying them on at a distributor in Emeryville, I sadly found that even the small was too large for me (I'm a thin woman.) While I believe that's the superior vest, it's also twice the price, so that's the other downside.
Overall I'm happy with how the Hit-Air RS-1 performed, and if it wasn't repairable, I had planned on purchasing a new one. But even the repair is cheaper than having to send an Alpinestars or Dainese suit in to be re-packed after deploying, which is about $200-$300 each time. The other downside with the other brands, is that they don't puff up as much around the neck. They may protect your collarbone from being broken by your helmet, but they aren't doing a whole lot to protect your neck, which is super vulnerable, and the main reason I wanted a vest in the first place.