We have a Weima WLK4 that we are going on 2 years. Push the green button when the hopper is full a few times a day and walk away. No issues whatsoever, and nobody goes very far to empty small trash cans, or gets on the forklift. We've done the dumping hoppers and had a high speed hammermill that was set up more for solid wood rippings for 15 plus years.
As far as noise goes, I would equate it to a spoilboard being surfaced. It's not at all uncomfortable with foam earplugs.
The ROI is almost too good to be true, set it up as close to your cut out area as possible and throw out the trash can and sell your hoppers, it will literally pay for itself in a couple of years when you figure the savings of, sizing pieces to fit in the dumpster, walking and driving outside emptying hoppers and the dumpster being full of air space. Not to mention the smoke breaks taken as part of going outside, and the loss of heat here in the winter every time the overhead door goes up. The space our takes up is roughly the same as our self dumping hopper. You can get an auger system to go through a wall and into your dumpster, set up a cyclone dust collector to have an airlock that gravity dumps directly into your dumpster, or even auger into your hopper get emptied 5 times less and still realize a gain.
The waste/offal handling side is grossly overlooked in our industry. We all focus on these huge gains in productivity like faster cut out and higher capacities that create more scraps, yet very few every consider the big picture savings of time and non-value added costs associated with internally moving and paying to have waste dumped and we don't evolve the whole system.
Grinders and waste handling is always overlooked because it isn't directly tied to your profits, but, they allow you to keep more of the money you've made. Contact Weima, we found them to be helpful and honest in guiding us and would buy from them again.