We've only been using these for a few days, but I'm pleased. Before, I used a paint palette for my toddler which always ended up being a timely cleanup and wasteful. With these I just close the top on unused paint and it keeps until the next time we paint and does not dry out. The opening in the lid only allows for small to medium brushes to be inserted. Since, we use sponge brushes, I just take the lid off while we're painting. I've never had a cup tip over, their shape, weight and design seem to help with that. Overall, I'm very happy and will probably purchase more for my little Picasso.As a former teacher, this is all I would use. One little trick I use is to line the cup with a zip loc bag, fill with paint, put on the top, and when the kids are finished, there is NO CLEAN-UP. If a lot of paint is left over, remove the lids and zip the bag closed until the next use. If all the paint is gone, simply remove the bag and throw away........no messy cups to scrub with dried on paint.these are easy to open and close. My wife also attached velcro to the bottom so it doesn't tip over easily.My grand daughter loved this! (Past tense because she used it all so quickly! Time to get more for her. Love feeding the young imagination!We have not had a spill yet! The paint in the cups stays fresh, thought the kids do keep putting the wrong brush with paint in the other containers. Kids love them!My 3 year old granddaughters use these easily and have no spills. Keeps the paint brushes upright, helps take off a bit of the paint, and stors the paint well.Paint doesn't spill. Best with thin paint brushes, large one are too difficult to use with the cups.Unfortunately one arrived broken but it's a good product.Didn't fit in my Alex art easel.