Bests & Worsts Reviews from Amazon

I'm very disappointed in the Roomba 870. I have all tile floors, and the roomba does a great job picking up hair and large debris. It leaves a tremendous level of small debris, enough to make a large pile on the floor. If I set the roomba to clean in the small pile, it just moves all the debris around not picking it up. I don't know if there's a problem, and will be calling support to try and find an answer, but it's a ridiculous level of stuff it leaves on the ground. I'm at a loss here. It does fill up with hair and other things, so it's not like it's completely not working. Just doesn't work for small debris for me. Edit: Spoke to IRobot support, they say that the 870 is not designed to pick up on tile, and that I should return it and purchase a model that uses brushes instead of the extractors. Very disappointed as all of the product documentation says it's for all floor types. I am going to take some video of the robot in action, and also try to compare it to picking up on carpets.