Like most 'affordable' Stabilizing Vests on the market, build quality isn't really an issue for me. The problem I have is that they require a very heavy 'minimum' amount of load weight to work properly. Here's a great review about the Wondlan Leopard IV Stabilizer System from YouTube member Landon Donoho [Thanks Landon], but you'll notice they had to add a 10lb block of weight to the top of their Sony FS700 to get these results.
Due to the fact that the Wondlan Leopard IV needs at least this type of weight to fly, this could be a very good unit for RED EPIC or Scarlet shooters. For more info on the Wondlan Leopard IV products, you can visit the product listings via eBay (found here).
Wondlan Leopard IV Camera Vest Video Stabilizer System