You will probably see a lot of negative reviews on this sight, but you probably will see the same for every other company.
Most of these posts have to do with the device side of things, and that is where I am. However, I do have friends on the other side of the bag, and most of them have done pretty well over the last couple of years. KC is a better supply company than device at this point. They have a good reputation on that side of things.
Overall, KC is a very large, conservative, stable company. Check out the financials. It is not going anywhere. Especially the supplies. As far as your success goes, it will depend on the contract situation with your products in your area. That would be a good question to ask. Also, I have heard there has been price increase for raw materials for gloves. I would ask about that, also.