About 2 years ago, we purchased a brand new Amana Radarange Microwave Oven for use at work. And like all of the microwaves currently being sold these days, the Amana Radarange Microwave has a glass turntable that sits on top of a plastic roller ring. We use this microwave frequently for reheating leftovers throughout the day, and over the span of two years, the plastic roller ring has been gradually chipping away at the enamel paint that coats the bottom of the microwave. Once the paint began to chip, steam was able to enter exposed areas of the enamel and cause bubbling paint as well. This looks absolutely horrible. I clean this microwave every night that I'm at work, and I'm constantly picking up fresh paint chips with my cleaning cloth. Seriously, I would throw this microwave out because it looks like trash, but this problem is common with every microwave model that uses a plastic roller ring.
At home, I have a 1987 Sharp Carousel Microwave that I've been using for over twenty years now, and the enamel has never chipped away or bubbled in all the time I've owned it. Why? Because the Sharp Carousel Microwave uses inlaid rollers that never move from their set positions in the bottom of the microwave, but will still allow the glass turntable to spin freely on top. Every time I'm out shopping, I look in the microwave section to see if any model is using inlaid rollers no matter how expensive it might be so that I can replace my old microwave with something smaller and more efficient, but they all use removable plastic roller rings. And I absolutely refuse to buy a microwave with a plastic roller ring because I know it will look like trash in two years or less. Even Sharp doesn't make microwaves with inlaid rollers anymore. And that's a gosh darned shame because I know that better quality microwaves actually do exist. I already own one.