Since I have not handled this armour I cannot say how good or bad the plastic is. I know a lot of people worry about thin plastic and as long as it is flexible, it should be fine. I prefer my 1.5mm flexible ABS over my rigid 2mm ABS any day of the week, but that is just my preference.
With regards to the kidney plate edges being paper thin, that is down to the shape of the part. The plastic does thin down quite a lot in this area, but I read that Anovos was supposed to be using two different gauges of ABS to cope with larger and smaller parts?